Check out Intel's web site.

They've already scaled the successor to the StrongARM (the XScale?) to 1 Ghz! What's amazing is that the power usage is the same as current StrongARM in the Compaq iPAQ (which runs at 206 Mhz). So you should get approximately the same heat levels and battery life as the current iPAQ, but running five times faster. Hopefully Palm and Handspring will match this, otherwise, look for trouble. I'm already seriously considering the next iPAQ -- 64 MB of RAM, 32 MB of ROM, and a 400 Mhz processor. Hopefully Palm will beef up their kernel to stay up to speed.