Lumileds' optics - specifically the NX05 optical collimator - are mainstays of the parts bins of most enthusiasts here. I have several lying around, in fact.
As for the Xitanium, they're big bricks compared to the drivers used by most modders here. Their size tends to make them unusable for flashlights, etc.
Lumileds has a 30mm optic out, which you can get from several sources here. (Wayne lists them on his Elektrolumens site, for example.)
Fraen also makes 30mm optics, and they offer multiple output beam angles. I've got more info on them posted here. Fraen is not yet selling them in small qty. but is supposedly hooking up with Future Electronics to sell them. If you only need one, you might be able to get a sample - one of the Fraen crew hangs out here.
It sure would be nice if some of you who's just doing this for the hell of it, would make a "how to make a step up circuit" tutorial, with parts and tecniques
I have someone who can help me make it, but not design it.
I don't want to buy the bad boy's at 22$ + tax + shipping and not knowing when they'll arrive and whether I can get more when I need them.