Good news! The 6Z body does accept an 18650 battery, the battery can only be loaded via the tail cap end though.
View attachment 57328
The above photo shows the new 6Z body fitted with parts from a round body 6P and a set of Surefire grip rings installed.
Damn, that is really cool! Thanks for the info Dave D!
I followed the link and purchased a 6Z body and 9Z body (stated it was the last one?). Hopefully my parts are also bored for 18mm cells. I want to run the 6Z with my Malkoff M61WL SST20 high CRI and with a 3.7V incan drop in and the 9Z with a 7.4V incan drop in. However to run incan in these bodies, I will use the hex head (boro lens) so as to not ruin the lexan lenses. When I run the Malkoff, I can use the smooth head as the LED will not harm it.
I do have mint condition 6Zs in the two styles they had (one with the two flat rings and the flared ring, and another 6Z with the three flat rings and flared ring. Both of these classics are cool in that they are super short.
I also have two Z2s (one mint, one new in package) (both are hex heads, one is the lexan hex head and the other is the boro lens hex head).
I also have two Z3s. Both in mint condition. Both have hex head, but again, one is lexan lens, and the other is boro lens.
These new bodies that I will piece together, I can kind of treat them as light "users" (ha ha) while the others make appearances once in a while.
I'll also report when the bodies come in whether they are 18mm bored :^P