I allready have done so. Do yourself a favour and read post above. In
two of them I wrote that the head is glued and cant be removed. Of course
if you risk breaking something you may be able to unscrew it. I dont want to.
Maybe a diffuser like http://www.manafont.com/product_info.php/fenix-diffuser-lens-ad401-p-5791 can work for you. The MC10 comes with a similar one, if I'm not mistaken.
Nautic, the diameters fit?
@ Haggai: No, different diameters, see post #31 above.
I have three of these now, excellent little lights IMO, much better build quality than you'd think from the seller's pics. Usefully bright on AA, much more so on 14500. Throwy beam is the only downside I can think of; if it was floodier this would be my perfect work/glovebox light. Tail magnet is just brilliant. Still looking for a suitable diffuser..
LOL, and I was the one who said it then too... 
That little Z1 is very tempting, but so far I've resisted CR123 size lights. No aversion to them as such, just trying to keep my battery choices simple. Also, the Z1 has no tail magnet. Now that I've used an angle light that has this oh-so-cool feature I don't think I could go back..
I have the green one, its very hot on 14500, works with ni-mh. It has some hiss sound on ni-mh after 20-30 minutes.
was able to unscrew mine. was glued on, brute force worked, I scratched the finish a bit.
two cables broke, but no worries. gonna install floody optics, as detailed here:
http://club.dx.com/forums/forums.dx/threadid.1167065
I am new to modding, anyone think this could fit?
http://www.shiningbeam.com/servlet/the-176/3-dsh-Mode-Regulated-Circuit-Board/Detail