Alph, a lot of instrument and running lights (1157/1156 bulbs) now have improved, or brighter direct replacement bulbs. If you find better/brighter bulbs for the IS trunk, please let us know.
Might be worth a phone call to a place like Radianz or other big light vendor.
i'll let you know jess, we've got a book at work that gives the specifications for 10,000's of electronic items from light bulbs to dimmer dials!! if it's not in there, then i'll have some hunting to do.....