I noticed on ebay and elsewhere they are selling bulb only (in other words without the housing/plug) replacements for the HC series of projectors- HC1500,HC1600, HC3000. Has anyone had any success with these?

I'd be interested in this as well, i've seen them for all models of projector it seems. But I've also read that on a GOOD day you'll only get 70% of the original brightness and longevity compared to an OEM lamp. I'd also expect that a generic bulb replacement might also not be tuned to the correct color temperature. To me it didn't seem worth it at the time to save $100

I've purchased the bare bulbs for my Optoma H77 with good success. If you take your bulb out of the housing you will see you can find the OEM replacement most of the time, not a generic bulb.