A few notes on the discussion concerning a possible G5 PowerBook (PPC970 processor).
First, the PPC970 can't use an L3 cache, it isn't designed that way. So even if you wanted one you couldn't have it (it isn't needed anyway, so the absence of an L3 cache is no big deal).
Second, a 1.2GHz PPC970 doesn't dissipate any more power than the existing 1.0GHz G4 (MPC7455). Also, the PPC970 can support dynamic clock-speed adjustments for power savings. In fact the dual 2.0GHz Power Mac G5 throttles back to just 1.3GHz when the system is under light load (this helps keep the system cool and significantly reduces power consumption).
Thus, given all of the above I believe that the current PPC970 could be used in a PowerBook G5 design (most likely at the 1.2GHz speed).
However, I don't expect that we'll see a G5-based PowerBook until first quarter of next year. Also, I don't expect PowerBook updates this week either, perhaps next week or at the Paris Apple Expo.