well, i think that with such a small portable device, nokia can't afford to put in more powerful chips that are power-hungry. my guess is that maybe we can push the arm arch up to maybe 600-800mhz, but nothing substantial enough to allow say, 800x480 h.264 decoding - even the mp3 codec is hardware based, so i think that once we hit the arm proc limit, nokia will probably add on hardware support codec support for formats like h.264 (imagine h.264 video conferencing!) or a chip for basic opengl support (it's all in the gui =P )

also, VMs on anything but top notch hardware usually results in a lot of performance degredation, esp. if you try to emulate hardware features in software (and esp. esp. when your software is running on a slow proc)

as much as i would like to see compatability of software between 770 and n800, i don't think it will happen because it's not cost effective for nokia