Hmm, don't know if I've seen one that will take both a C/P/Z (surefire) head or tail. But I think you are almost out of luck.
I've got a bunch in the the basement - but off the top of my head the body is ~1" or 25.4mm, a 26650 is 26mm in diameter (the first two numbers, the 65 is 65mm in length). So you are pretty much out of luck on heads and/or tails - you wouldn't be able to get a battery in (both ways).
So you would need something custom "for a drop-in" - TnC has them (link below) - the P60/D26 is the designation for the drop-in, but won't take heads & tails.
Be interested if someone else has something...., I'll be embarrassed if I have it downstairs.
http://ogazent.com/cscart/index.php?dispatch=categories.view&category_id=6
