Although I do not yet have any working IR source (another story), I have tested my Lifecam HD-5000 with one of the SFH485P IR LEDs, without any internal modification, and the camera sees the LED very well. The only thing I did was add a piece of floppy disc material over the lens to filter out most of the visible light.
As soon as I can figure out how to get the 3-LED light system working, I'll post a better report. But there should be no problems with using this camera straight up with the floppy filter added.
Well, I'm now on the hunt for photo negative film. Do you know how hard it is to find that stuff in this digital age? I think my wife has some old photos with the negatives (which usually has some blank frames), and I'll try that.
However, even using the floppy filter, I'm getting a fairly bright "dot" on my camera. I'll let you know what happens.