Went through EVERYTHING including downgrading the "ABI" culprit (xbase-clients), playing with all the apparently duplicated fonts paths, etc. to no avail. Today there was a new xorg module upgrade on Sid. This fixed it! Yes, I know ... it's "unstable". However, posting something that will render so many systems unusable is not so nice. Wait a day or two till the upgrade picture is more complete and then post it, please.