I'd like to see a Kel Tec P-22 in 22 LR. With the Walther TPH's out of production, this might be a good seller, as there is nothing available right now to fill that niche.
What else...How about a S&W L-frame in .45 Colt, the return of the Browning B-92 in 357 magnum, or a new Mauser Broomhandle in modern calibers?
How about somebody making a carbine in 357 Sig? Especially a Beretta Storm? That'd be pretty cool. I'd also like to see a High Power in 357 Sig as well. Come to think of it, a P-7 in 357 would be uber-cool to boot!