Hmm, interesting. What is the replacement procedure like?
Projector bulb cages are cast alunimin with a glass refactor inside. The bulb is mounted via a hole in the glass refactor with plaster that can be soaked in water and ice picked out. You can remount the new bulb with about anything that handles high temps well. Some have used muffler patch. I prefer using something that can be removed again like a high temperature plaster.
Basicly it makes more sense to me every 2000 hours to spend $65 + do the labor than to spend $350 and drop a new lamp cage in. I have 4 lamp cages, 2 currently with good bulbs. I can afford the time to have my backup lamp plaster set with no downtime because I already have one done currently for backup. Anyone that has projectors most likely has 1 lamp cage with a burnt out bulb sitting around someplace. Just fix it for $65. :)