Honestly, I think the Pandora has enough pixel density. It's practically impossible to see individual pixels. Given that, how useful would a higher resolution actually be?
On the other hand, maybe a fake higher-res (e.g. 1200x720, 50% bigger) might be useful, i.e. on the software level it's the higher resolution, but it actually displays at 800x480. This can be experimented with the current Pandora too. Actually, you can get a pretty good idea of how useful it would be by resizing a screenshot. This is from Windows, but this is a resized version of a crop of a screenshot that was 1200x720:
http://img580.images...32/highresu.png
I looked at that on my Pandora, and it honestly looks quite nice. Everything is still readable, and it's incredibly difficult to notice that it's scaled. The only real problem is that the text is so small, but that would be present with the resolution being actually bigger as well.
(BTW, I did this in MS Paint. I just used the "Resize" option.)