According to macnews.net.tc, new PowerBooks are expected in mid to late October. The 17" and the high end 15" are said to get a 1.8 GHz G4 (7448) while the low end 15" and the 12" will be boosted to 1.6 GHz. The 17" and 15" will reportedly get a Radeon Mobility 9800 whereas the 12" will still be stuck with the 5200 FX but its price will be lowered by $100. All in all, this would be a nice upgrade for the last AlBook revision.
Link:
http://macintosh.fryke.com/cgi-bin/macnews.cgi/2004/09/23#20040923_pbs
Link:
http://macintosh.fryke.com/cgi-bin/macnews.cgi/2004/09/23#20040923_pbs