I've asked this elsewhere, but in case there are different users in different parts of the "internet" I thought I'd ask here.
As I'm a 4x5 user as well I like being able to use lens movements on other cameras. When I used 35mm film I used Canon TS-E lenses and liked them a lot. Since I went to digital (APS and more recently 4/3rds) I ended up selling the TS-E stuff. But I miss the ability.
I think that with the micro 4/3rds there is plenty of scope for a lens adaptor to include ability to move the lens. Since 35mm lenses have plenty of coverage I thought that they would adapt well to a tilt adaptor. I fleshed out my idea on my blog page here.
Essentially though given focal lengths and sensor size relationships I think that for normal lenses shift is un-needed and a tilt only adaptor would be nice, and for wides (like 16mm or less) that a shift adaptor would be nice (with tilt not adding much benefit compared to larger formats).
Since I don't make things like this I wonder if enough people are keen on this to encourage any of the existing adaptor makers to make one?