Looks very interesting.
For a super wide and shift mf system to go in combination with mf slr (contax 645) I was going to look at the silvestri bicam 7000 that gives 15mm shift, 24mm lens upwards, is pretty compact, takes film backs and digital backs and the helical mounts are not as overpriced as the cambo system...i was looking at this over the cambo wds due to smaller size and easier on the wallet to add lenses.
If I can wait it will be good to get more details of the arca system..i.e. how much rise, shift, and price of body, back, db adapters, focussing aids, etc, etc.
marc