I just got my 1x26650 from BigHonu (secondhand), but I thought I'd add my two cents to this post in case this info helps anybody:
Build quality is great. It's the most grippy flashlight I own. Integrated lip in the battery tube so the battery doesn't fall out when you change the D36 module.
O-ring on top of the glass, 1 o-ring on the bezel side of the body, 2x o-rings on the tailcap. Tailcap uses an oversized spacer to hold a standard type Surefire clicky (or in this case a McClicky).
I'm looking forward to using the SST-50 at 2.5 amps, and the XP-G R4 at 1.4 amp D36 Nailbender drop-ins when it gets dark tonight.