Believe it or not I still have an ACR Firefly 4G. I had two but one's bulb finally gave out.

It might have actually been on this site years ago that I found a link to a guy who made a cap that converted the battery from the funky chapstick style lithium to CR123s.

I still carry mine on my overnights. But mostly its a novelty with the kids. The only thing I don't have the cool lace up LBE pouch for it. I have it stuffed in a stretched out LBE compass pouch.