"We have no idea how the device works because the only information out there is a single computer generated image."
No we have no idea if the device exists other than as a series of computer generated external images (unless others know of further info or a link to it).
But to go from a reasonable suspicion that this particular device does not exist to a position of arguing that it is not possible to do what the device is supposed to do as the reason it is not real is not a reasonable argument.
All I have simply pointed out is some moderatly simple methods by which people can see that such a thing is potentialy possible.
That is this specific device may or may not exist but in principle there is no real reason to think it can be done one way or another on a pin by pin basis in simpler locks.
You however have arguments such as,
"I'd be interested to see any practical way of having 5 or more magnetic pickup cartridge like arrangements in something that fits into a keyway. That's a very small space."
You are boxing yourself in with your own view point.
For instance try asking yourself the question,
'Why do I need five sensors?"
The simple answer is you don't.
Thus you are limiting your thinking process by raising a false barrier.
Most people who have picked the simpler tumbler locks know you effectivly open the lock a pin at a time. Likewise with mechanical key impresioning you usualy do it a pin at a time.
All the device has to do is measure each pin in turn.
How it does five / seven / twenty pins as opposed to one pin is not of that much relevance in deciding if it is possible to make a mesurment of a single pin or not.
The important first step from the security asspect is "can a pin be measured this way".
Further if you think about it all a single pin measure has to do is deduce from each measurment it takes of the pin the length of the botom part of each split pin. And normalise that against the lock manufactures usual cut depths.
The device has absolutly not need to convert the readings into the maufactures "Key Code". The pin length information is enough to make a key from. Thus this "key code" convertion is I suspect an attempt at "security by obscurity" and an acknowledgment of trying to stop "non trade" people using the information to keep the "trade" happy (which arguably adds credence to the idea).
You apear to be quite hung up on the idea that the pin needs to be moved up (or down) in the barrel to determine it's length. You say,
"The other issue is with the movement of pins. You need to move the pin gradually downwards until it stops binding."
Again with a little further thinking you realise that to measure the pin length you do not need to move it up or down the pin channel in the lock barrel to find it's non bite position.
All you need to know is the aproximate hight from a fixed point of refrence in the keyway that the botom of all the pins align to and the length of the bottom part of each split pin.
This becomes obvious when you think about the basic idea behind a "Bump key". The bump key uses the idea that if you couple enough mechanical energy into the bottom part of the split pin the top part like a Newton's cradle will jump away out of the barrel, and if you get your timing right you will be able to rotate the barrel open, importantly the bottom part of the pin stays in the barrel.
This lack of further thought again limit's your outlook as your comment,
"A pickup like you mention is very sensitive, but only over a very narrow range of movement."
Your view point might be the norm for those regarding lockpicking and impresioning from a distance. But this is due to human inabilities not to the limitations of measuring.
If you think about it geologists don't drill down to rock layers to find out how deep down they are, it's impractical so they use a different method.
So another question for you to ponder,
'Do you need to move the pin to measure it's length?'
Again the answer is no.
All you need to do is have contact with the bottom of the pin and give it a very small impulse and then use the return echo from the pin to determin it's length. This is what my earlier comment,
'Think of it if you will as a combined thumper and geophone to make a micro seismograph to sound out the the layers in the lock...'
There are already (relativly) cheap devices that meaure the thickness of coatings such as paint. For instance some of the Police in London have a pocket version of a paint thickness measuring device that they use to see if a car has been "re-sprayed" and thus may be a stolen item.
So rather than saying it's not possable as you cannot immediatly see how to do it, or do not have technical drawings you can assess, or have not had a demonstration of a working device in your hand, try thinking in a different way.
Boxing yourself in is a very bad mindset to be in for "security" thinking.
That is ask yourself how you might go about attacking a system. And only when you can reasonably rule out all the possible ways can you say that a device to do this could not be made.
So have a think about all the number of ways.
Say for instance a probe about the same general size as a bump key, on the leading edge a pizo or synthetic crystal sensor.
When in contact with the bottom off a pin it sends an impulse into it, and also measures the return signal time delay in exactly the same way as radar sonar and siesmographs or other Time Domain Reflectomatry (TDR) measurment.
So we can visualise such a device and a principle by which it could work. So now we know in principle it is possible to do which makes your comment,
"All of what you are saying is a bit of a straw man argument."
More aplicable to yourself. (Assuming you are going with the US meaning of the phrase not the original English meaning of a "witness to rent to commit purjury").
You go on to say,
"You don't know that it exists"
I have never said it did, all I trying to point out a number of general principles by which it could work reasonably be expected to work.
Thus If we can rule them all out then we can say the device probably does not exist (assuming we can identify all the principles by which it may work). But not otherwise.
Which is why I'm not as you say,
"... and try blinding everyone with vaguely related concepts."
It is these same "vague ideas" that design engineers and inventors use to come up with new and inovative products.
Which brings us onto your final paragraph,
"My point being - doing this would be a large technical challenge. Nothing similar has been produced before"
I'm not sure it is a technical chalenge it depends largly on your meaning. Yes it would be a chalenge making a prototype but not overly so. As I have noted there are several not too dificult to understand principles that can be used.
" it's certainly not a case of standing on the shoulder's of giants."
I'm not sure if you know thet Newton used the statment as an insult to others who he felt had delayed his work by not releasing their data to him when he demanded it. If you have another meaning then it is not overly clear.
You then go on to express a personal view point without any real supporting evidence with,
"The demand for this will not be particularly high because impressioning kits are cheap and work well."
You appear to be assuming that a person can first be bothered to learn how to use the impressioning kit. As we know there are a number of faux locksmiths in it for the money who just "drill or kill" the lock (ie no skill required but a high fee charged).
Then there is the question of if a sufficiently skilled person is prepared to spend the 20minutes or so to do an impression on a street corner late at night with a frustrated customer breathing down their neck.
Or worse some thief who is waiting for the locksmith to turn their back so they can be mugged for their tools van keys etc etc.
Let me ask you to ponder this,
If you had to visit the rougher parts of any major city such as Washington, New York, London, Paris etc etc to help a "stranded maiden" get back into her car in the early hours of the morning, I suspect you would be very interested in a device you could just shove in the lock and then plug into your CNC style key cutting machine back in your van. Where you cannot be easily jumped etc.
Oh speaking of that time of day, the next time you get "a fit of the tweeters in the Midnight Hour" just remeber it might come back to haunt you.
Anyway it's up to you but try climbing out of the box and having a sideways think, you might get to enjoy the experiance as it will hopefully open up your horizons.