czyli:
I just spoke to a very well connected friend (don't ask his title please,) at Canon regarding the Canon 1D Mk3 focusing issues. Canon has a firmware fix in the works and is currently testing it in the field. The problem has involved what amounts to silent firmware upgrades to a number of lenses that have been made over the last few years, upgrades in anticipation of new proprietary focusing algorithms.
He believes an announcement is forthcoming soon .
Incidentally, I have two very early serial MK3's, and they run circles around my 1D2's.
Things are looking up!