Here are some recent resources I've found regarding spectral sensitizing, from the holography folks.

http://holoforum.org/forum/viewtopic.php?f=9&t=494
http://holoforum.org/oldforum/viewtopic.php?f=2&t=6540
http://holoforum.org/oldforum/viewto...d1e5f1831248b9

Apparently these are sensitizing dyes as well. Possibly very expensive(?, not sure...)
http://www.organica.de/en/Products/49,Functional_Dyes

Very interesting opportunity to get pinacyanol chloride
http://www.9000shops.com/holodye/index.html

via Jeff Blyth
http://cabd0.tripod.com/holograms/index.html

And haven't even read this, but it looks interesting...
The Action of Optical Sensitizers on the Photographic Plate, G. Kornfeld. Kodak Research Laboratories, Rochester, New York. Received May 25, 1938.
http://www.nap.edu/openbook.php?record_id=9565&page=97