Some kind of firearm that seems totally feasible with today's technology that nobody has made yet (No phased plasma rifles in the 40 watt range). I've always wanted someone to make a modern double stack polymer pistol chambered in 7.62x25 tokarev. It's a pretty potent round, milsurp is dirt cheap, and they're narrow enough that you could probably fit 25 of them into a full size magazine. It sucks that there are so few options for that caliber.
So, what have you always wanted to see?
So, what have you always wanted to see?