Which leads me to wonder why the ts/e lenses don't have a mount for a tripod collar.
The engineering to support the weight of a camera would make the shift mechanism extremely solid.
If you've got one, attach a TS lens to something heavy like a 1Ds and try holding it by the lens while altering vertical movement ... not something I'd try with one of mine BTW ;-)
There are various tripod adaptors that allow for precision shifting of the camera - just a bit of hassle to set up and use in a hurry.
Such a heavy duty version would have a very limited market for what is a specialised lens anyway - I once heard that Canon sold so few it was a bit of a loss leader. However they seem much more popular now, even to the extent that I've heard of rumours about an all new TS-E next year (which would be nice :-)