I have to admit that I did not read all 15 pages of posts (I'll save them for a rainy day

) , so this may have been said. But I think the reason for dropping Power from the name of the PowerBook is that Power may have been a reference to the PowerPC.
So, Powerbook became MacBook Pro
However, the iMac retained its name. Therefore, I hypothesize that the iBook will retain its name as well. However, since Power Mac refers to a PowerPC product, I hypothesize it will become MacPro or Mac Pro.
So, an "i" in front will refer to a consumer product, and a "pro" in the rear will refer to a professional product.
I agree I am not in love with the name at the moment, just trying to rationalize it