I see tripwire has considered the dual handcannon idea...

[YoYoBatty]

If you remember a thread that was made a few months ago suggestion you should be able to switch which handcannon was shot if using dualies, then I am proud to say that TWI is considering this. If you want to see this for yourself then open Killing Floor SDK and go to animations browser and open the Dual50_Trip animations. Basically when in iron sights you can switch between handcannons for increased accuracy.