Err why must it contain either the words 'Mac' or make it that obvious it's a laptop? The iPod doesn't, and no one has problems understanding it.
Apple succeed when they are bold, and think differently. As has already been pointed out, MacBook is horribly similar to QuickBooks, that 'orrible accounting software way back.
I'd have gone for something like iBook. Oh, wait...
MacBook... what else could it have been?