It's also a bit difficult. With Apple actually being the _sole_ computer vendor to actually make use of the PowerPC as a desktop and notebook processor (yes, there are others, but they are _very_ small players and for this thought don't even matter), we only see what IBM can deliver if Apple shows us. IBM, for what it's worth, could deliver a G5 notebook processor running at 2.5+ GHz right _now_, and as long as Apple doesn't produce a computer that makes use of it, for what we know, IBM didn't deliver.
Once Apple jumps boat, IBM simply _won't_ deliver desktop and notebook PowerPC processors. And we won't know where they would have driven. We'll only see what they'll do with the POWER series and with the console chips (and those are updated every other year at best).
Btw.: I thought we already discussed this about two weeks ago or so...
Mac user since 1987. Running Mac OS X 10.8 Mountain Lion on a MacBook Air 11" & an iMac 27" and whatever's newest for my iPhone 4s, iPad 3 and AppleTV 2.
Apple Certified System Administrator 10.6, Apple Sales Professional 2008-2011, Apple Certified Mac Technician.