Is the issue of video drivers the only real hurdle? If so, are there any plans to add Radeon-based TiBooks to the compatibility list? I'd certainly be up for giving it a shot on mine.
You could ask Piru, but my guess would be no.
There's only so many models they have time to develop support for, and I think their intention was to support just a few really good choices.
Athough I doubt we'll get it, personally I'd like to see G5 support.
A completely unsupported guess, eventually we might see a move to ARM.