I think that it's possible to put dual processors in some of the PowerBook models that are available using 90nm technology (90nm should keep the system much cooler). I've seen this done in notebook PCs before. This is how I see a future lineup of PowerBook G5s (in 6 months or more, PowerMac G5s should be running at much higher clock speeds than they are now): 17" -- DP 2.2GHz G5 15.4" -- DP 2.0GHz G5 15.4" -- DP 1.8GHz G5 15.4" -- SP 1.8GHz G5 12" -- SP 1.8GHz G5 edit: What if by default the second processor was turned off? The user could turn it on in the operating system control panel if they need it for doing highly intensive processing tasks. Even then, the operating system should control the use of the second processor by limiting the use of it; this is just the same way that the OS manges the fans in the PowerMac G5. The OS could manage it in such a way as to keep the heat down and battery life relatively high. That just might work.