Just for those who don't know:
Regarding the Quark Pro and Tactical user interface, and I am at least as big a fan as anyone of those, it can't come back. Suefire closed the door on that in their legal settlement with FourSevens. The head twist is not going to change the brightness of the light.
But I would be all for a thread-compatible series with a new and innovative interface. Maybe like the Quark Click, but with a more open, user programmable interface. Pick how many modes, 1 to 5 (plus possible blinkies, if you have to) and which ones if less than 5, ascending or descending, with memory or with a default mode - say lowest when ascending brightness and highest when descending brightness. I'd buy that in a heartbeat! Lego ready!
Maybe it could have a few popular pre-set interfaces for the masses, plus a "full programmable" interface for, you know, REAL men.