intel is currently supplying many 3ghz processors for the Mac Pro's, the Quad 3.0ghz being bespoke just for apple.
but not for portables. as far as i know, you can't get a fast (you can possibly find a dogged old P4 3.2ghz knocking around) 3ghz cpu for a portable, the fastest is the 2.6ghz found in the highend MBP.
3,000,000,000 cycles of process per second generates a lot of heat. it'll be a while before we break through that barrier. most modern laptops are now called notebooks anyway, as they all run far too hot to be deemed comfortable enough to have on your lap...