Hmm, bandwidth issues with the possibility of only 640x480?

Without knowing any details whatsoever, you could circumvent that by drawing to an XSP 480 x 240 pixel buffer surely? Failing that, just use the hardware to setup transforms; models; etc and slowly writing them to a buffer somewhere would still be useful.

The E90 happily utilizes PowerVR. http://www.youtube.com/watch?v=Q-mEgsr4qcs - screen is 800 x 352