This looks extremely interesting! I love that the cell is replaceable but the light is kept compact. That's the point of this light really, a big tail cap with springs would kinda defeat the purpose imo.
Here's two questions I'd love to get answered by Wuben:
1) Is the bezel around the TIR optic glued? Or can it be unscrewed with enough force?
2) What is the user interface like? Is it one click for on, one for off? And if so, is there a lockout mode? I'd love to see either double click for on, or a lockout mode that requires three or four clicks to lock/unlock.