[fencepost]

I feel like developing something that could actually pick locks including detecting binding pins, etc. is in the category of "not actually that hard if you devote the resources to it."

On the mechanical side there would certainly be some challenges (having to work within a key that's all the deepest cuts, using something that could push up to "shallowest cut" level without deforming, general structural strength problems) but once you had a viable insertable key portion built you might be able to read a lock based just on the amount of spring resistance at each pin. You could also provide tension while probing for pins under tension. If covert agencies don't already have pretty portable devices like that it's because they don't care enough to create them not because of some true technical problem with doing so.

[cloudfudge]

I think the biggest problem is that the amount of tension you need to apply to hold the binding pins can vary quite a bit, and it's hard to build a mechanical device that can feel with enough fidelity to figure it out.

[fencepost]

Not really, once you have any materials issues with the vertical portion ironed out you just need a fine but rigid shaft within the body of the 'key' to bring it all the way out to where you have plenty of space to work. You'd need to have the shaft in a tight channel, but that's purely mechanical and should work just fine over even several inches.

[jiveturkey]

not at all. sensitive strain gauges are commonplace.

[cloudfudge]

I think if you actually tried to build this, you'd find that highly sensitive strain gauges are not sufficient. The human hand is extremely sensitive, and for example can detect tiny clicks and vibrations that you're not going to get with a simple strain gauge.