I recall at least two threads about it. Easy enough for me to do so any one over 8 or so would be able to do it.
Topper /ubbthreads/images/graemlins/smile.gif
You can buy a G2z tailcap form surefire, but it'll cost you a lot or you can mod the tailcap with the ozark AA trail light from walmart. I think the last time I was there (2 weeks ago) it was still there. The newer or older generation ozark trail lights will work.