The 80gb drives exist (don't remember which manufacturer), they'll almost certainly be in iPods announced at macworld. But no, no interface changes-- I think Apple is really happy with the click-wheel. Solves the problems that previous interfaces had, and it's still very much in line with their philosophy and aesthetic. So, I'd expect:
60gb and 80gb iPod photo
40gb and 60gb iPods (maybe 60/80, not sure)
5gb iPod minis, perhaps new colors, or tweaked finishes
a new special edition? Not sure which artists would be good for this. They won't update the U2 iPod obviously, but they've definitely opened the doors for future SEs.
paul