I think too much assumption is being placed on Apple even retaining the names PowerMac and PowerBook. Perhaps, although unlikely, Apple will rename both systems altogether.
How about "PowerNote" or "SubNote G6" or something.
And why not call the PowerMac something like the "Apple Neptune" or the "Macintosh PowerCat"
Remember, this is Apple and Steve has suddenly felt the need to "Think Different"
I will now accept your murderous responses!