Why not get a 7" Eee PC LCD screen and put it in the Pandora? They're 800x480 aren't they? All you lose is the speakers, a touch screen,and a lot of battery life.
Introducing the Pandora 9inch:

Seriously though, it would be really cool if someone did do a screen mod.
Impossible. Both most likely use different digital signals, which means you would have build and program a reencoder, which would kill the possibility of fitting it all in the pandora, making you lose the pocketability