Fostech Arms Origin-12 shotgun

This probably was the most innovative fire arm to show up. While they did not have their own booth, (they were part of a distributor's booth) it was impressive work.

This is AK-based shotgun you can change calibers and do not require AK-like rocking motion to insert magazine. You can also manipulate bolt lock, magazine release and safety with one hand.

Price is $2600

They also have their proprietary bumpfire slide, Bumpski(price is $449)

Link: Fostech Arms

Here's a review from Iraqveteran8888