Michael,
Great stuff, as always. You say goodbye to medium format at the end of the article - are we to take that literally, or will you still use medium format?
Regarding 4x5, I don't have a 1Ds, but I have downloaded and even printed a couple of tests shots others have done, and I agree they are impressive. My own view (as someone who drum scans his own 4x5 Velvia) is that 4x5 still has a reasonable quality lead, similar to the lead it has over, say 67. A LF tansparency, drum scanned, still has a richness of tonality, and rendition of fine detail not yet reached by a DSLR like the 1Ds. But it's still a stonking good peformance by the 1Ds.
I also need to be slowed down, and using LF or Medium format does this. I feel a bit silly mounting my Fuji S2 on a tripod in comparison.
Quentin