From Bob Peckham:

CONSULTING MEDIEVAL MANUSCRIPTS
http://webpages.charter.net/tbob/medmss.html

and have recently added a number of links. This will be transfered as
a part of a section on medieval manuscripts for the Andy Holt Virtual
Library.

It appears that the

Catalogue of Digitized Medieval Manuscripts
http://manuscripts.cmrs.ucla.edu/

has stopped adding new manuscripts to the database. I suspect they
are merely making adjustments, and hope that UCLA's $132 million
budget shortfall has nothing to to with this vital project.