Sorry to revive an older thread, but I have a couple questions for Kav. What time interval are you going to use, and just exactly how unattended does the camera need to be? I was thinking that a Hasselblad A32 back might work for you - certainly you can still get some color films in 220-size and getting them processed should not be a problem. You'll only get 32 shots instead of 100, but that's still a fairly large number of shots in one magazine. If your situation would let you reload periodically, might this work?