There was a G-36 Commando pack with tons of different silenced G-36s made awhile back, I'll see if I can find it...
Im sure theres a MP-5 out there with a reflex sight as well (you don't attach actuall sniper scopes like the one on te M-21 to SMGs, they're too inacurate. Reflex sights are more like the "scope" mounted on the XMS or the sights on the G36)