Updates:
Status: Invalid
Comment #1 on issue 2573 by [email protected]: feature request : text
markup in a tabstaff
http://code.google.com/p/lilypond/issues/detail?id=2573
It looks like the answer is at http://lists.gnu.org/archive/html/lilypond-user/2012-05/msg00696.html and the requested feature is already part of \tabFullNotation
