In talking to Calumet here in NYC, I've been told that the WDS adapters are optimized at the factory for the particular body they are mated to, so while you can swap adapters and it may work, they do not recommend it. As Pixjon, said, I've also been told that film and digital on the same body with digitar lenses does not work due to coverage issues. That said, I still have a hassy v mount back that I take with a few rolls of film if I'm going to a remote location, but I've never had my P25 go down (knock o wood). I figure even with the coverage issue any image is better than no image, but I also have the 1Ds as backup as well.
Using the Cambo with the 35 and 47 Digitars is a blast, Lcc's and all with the P25v. Switching between horizonatl and vert requires just the back to be rotated, and even shooting tethered, this setup is much faster than the old days of 4x5. 24mm is limited on shoft, but still very handy.
I am looking forward to the new Arca. Having tilt and a bayonet mount for lenses with helical focusing on the body seems very promising, not to mention the zoom viewfinder.