All models of the Mamiya C330 TLR have dual releases, including one near the base of the camera that works "front to back". If I cradle the camer in the palm of my left hand, my index finger falls naturally there - and there is no twisting of the body when you work that way.
The Mamiya TLRs are also some of the easiest to use cameras for left-handed people like me (I have limited strength and dexterity in my right hand).
Use a 10" cable release and tape it to your lens barrel... then as soon as you focus, you can "pull" the shutter button forward :) he he he A VERY professional look I'd imagine!
Actually - the cable release is not a bad idea - just keep it on at all times and tape or strap it to wherever is convenient!!! I am so going to try this! (like oh my god, I am such a teen age girl! ;) )
just get a TOPCON and you're set.
really great camera with amazing lenses - cheap too...