Keeping Apple's current trend of longer running 'books, they would probably stick in the ATI Radeon for two reasons:
1. Apple's long running relationship with ATI
2. Lower power consumption
I don't think they'll do anything with the screen because it would make the PB too big, but I do agree that the increased pixels would make os X look really great. I don't think that they would make the case any thicker, because one of the main reasons for making the TiBook that wide, but thin, was so that apple could laugh in the VAIO's face saying "look, I'm .15 inches thinner than you, have a faster processor, a dvd-rom drive, a HUGE screen, and a big hard drive, and you ain't got crap!" If you watched Steve's keynote when he introduced the TiBook, he kept referring to how much thinner the new PB was than the VAIO, and doing many feature compairsons. So, in short, if they did beef up the case, it would then make it THICKER than the VAIO, deafeating the whole purpose of making it that thin in the first place, and making Steve look like a really stupid guy for bragging about his new 'books features, and then a few months later, make it thicker than the one he was comparing it to. just a thought