Akkuhalle, thanks, that's pretty interesting, someone really is selling CR123-sized 3.6 volt li ion cells. They will probably burn out the lamp in some Surefires if you use them like 123's! In particular the incandescents and the L4. But the L4 would probably work well on just one of those 3.6 volt cells.
Are you the seller? I sent an ebay message to the seller asking if they can ship to the USA, but if you can sell direct on CPF, that's even better.