That thing was mentioned many times. Various people looked at it. Some (very few!) people have skills and knowledge to work at it - but, as all of us, they are busy people, and that project would give nothing but a lot of PITA and a small bit of credits (among those few who can understand the whole issue), so for a moment no timeline, no promises.
There is an idea that even collecting those dreams together in one place could be handy. May be, one day, we'll find the superhero... GSoC 2011?
Anyway, here is the place to express your ideas related to XKB2. The initial set was discussed with Andriy Rysin (the guy who manages XKB stuff in KDE).