PB G4 Upgrades
If Apple's previous product cycles are any indication, a major revamp isn't in the works. If you recall, Pismo was introduced at the start of 2000, and the only revisions that it got were an (undocumented) motherboard change in June/July (mostly to resolve problems with the FireWire ports not having enough power, thus creating problems with 3rd party devices like Orange Micro's iBot), and a boost in harddrive space in September from 6 to 10 in the low end and from 10 to (I think) 18 in the high end.
The only 2 things that should prompt a major upgrade in the PB G4 are:
1) That starting with the Pismo in early 2000, the entry level processor speed has been 400 Mhz and the high end has been 500 Mhz. G3, G4, whatever -- the Mhz configurations have remained stagnant, and that just is a little sorry considering the 900 Mhz laptops you can purchase for less than the TiBook from Dell, etc.
2) That the ATI 128 Mobility chip set is also pretty dated. It's time to move to NVIDIA like Dell and others have done.
A hard drive bump up would also be nice and is certainly possible...it's also a lot easier than putting in a new graphics board and the like.
Rather than expecting major overhauls (no way this soon after its introduction), a more likely strategy for Apple is a bit of a price cut, plus (1) and/or (2) above. I'm banking on the combination of price and features to be good enough for me to do my trade-in then....