Lightmalls shows the UF-V4 it takes a 14500 and says it's an XP-G. Guess this light will work with that headstrap from KD? I couldn't find a headstrap at Manafont. I see Lightmalls also has the Trustfire Z2 as well. From the beamshots on product pages it appears the UF-V4 puts out more flood (which I believe is more useful in a headlamp).
Edit - Here's the link to the "Ultrafire Elastic Belt" at KD and the BLF post about it. After re-reading that thread (in regards to the Trustfire Z1), I'm guessing I'd shoot for the Z2 and assume the reflector can be removed just like the Z1 for a beautifully even flood. And now I remember why I didn't like the Z1 - 16340 cells!
-Garry