I realize it doesn't mesh with the line on the roadmap itself (which appears to be ~12-28mm), but might the DA wide zoom finally be the Pentax version of Tokina's 11-16mm f2.8 AT-X Pro DX that ultra wide angle shooters really
should have already switched systems for?
That lens is so well regarded that a company actually sells a modified and reassembled version at a large (over five times) premium for the notoriously picky--not to mention, deep pocketed and to whom size and weight are not an issue--cinematographic crowd: the
Duclos 11-16mm.
Do they actually sell? "Current wait time: 5-6 months"
(Warning! Full Frame speculation ahead!:
It's also possible that it will be a port of Tokina's 24x36mm (or, incidentally and unimportantly, "Vista-Vision" in cine terms) version of said lens: the 16-28mm f2.8 AT-X Pro SD FX, the arrival of which on the roadmap [instead of the 11-16mm] would be enough of an indication of a 24x36mm body's imminent arrival that a little bit of fudging of the line on the roadmap would be in order.)