they may not be the cheapest, but the McR-XR reflectors from the sandwich shoppe are the only one to use with Crees - no rings at all + great beam
(but I dont like the 27 mm one - difficult to place and imho the 19 mm makes the best beam
+ with the 19 mm one can fit more of them into the host light)
Okay, I see where this specific reflector isn't just for the Seoul. I may have to get one and try it out for my project.
But do you think that reflector mentioned from Dealextreme may work as well as far as beam quality?