Oh you again. You never responded to my last pm.
Anyway, I'm one of those without problems, so this one will be difficult to track. And I have difficulty believing that the UI could even cause a linkdead, but you seem to have researched it to some extent...
Do you go linkdead while zoning or during normal gameplay?
If it is while zoning, try removing/renaming the eq2ui_hud_zoning.xml file.
If it is during normal gameplay, can you link it to specific actions? Otherwise all I can suggest is to start removing random windows until it stops.