Quote Originally Posted by Kjarahz View Post
The ability to hand hold like a DSLR, overall ergonomics. Eye level viewfinder. Interchangeable backs for color and b&w on demand without having to finish off said roll. Auto focus or a confirmation system to get shots off quicker. Metering if possible but I'm getting quite use to my light meter anyway. Lens availability and pricing, I shoot all kinds of things including skateboarding so a cheaper than $2,500 fisheye (Hasselblad) would be kind of nice, but not a deal breaker.

In the process I would rather not downgrade in quality but if I would I'd like to know in which way I would be.
DSLR handholdable: My m645AF is not much worse than my EOS 3 or 7D, depending on lens mounted. Example comparison here.

Swapping backs, that rules out Pentax 645 and 67, you've said Contax is too expensive, so all that's left is M645 and RB/RZ.

AF Confirm, that's pretty much M645AF (or the already ruled-out Contax, not sure about Pentax).

Lenses, M645 AF lenses are cheap, MF lenses are cheaper (except the 80/1.9 never got made into an AF version). About as cheap as you'll get in MF lenses except Soviet K60/K88 lenses which are a crapshoot (trust me, been there). Also as I've said, adapters let you keep the current ones you've got, even if only to use before you get native-mounts, and then IQ is exactly the same as before.

Fisheye, look into the Zodiak / Arsat / MC Arsat 30mm f/3.5. Blatant ripoff off the $2500 hassy, maybe not as good, but definitely only 1/10th - 1/20th of the price. Pentacon 6 and Kiev 88 mounts natively, maybe they made them in Hassy, definitely adaptable to any 645.