BTW, if I had to put money on the device's name, I would go with "iBook". It's classy, simple, and already trademarked. "Slate" sounds so Flintstones. Sure, there are old laptops that carry the iBook moniker, but Apple's re-branded/recycled stuff before.
13" Al MacBook -> 13" MacBook Pro
iPod -> iPod Classic
Intel renamings:
Power Mac -> Mac Pro, PowerBook -> MacBook Pro
"iBook" would fit its form factor, wouldn't use the "Mac" name (assuming that it doesn't use Mac OS X), and rolls off the tongue SO much better than "Magic Slate" or even anything using "tablet".
Mark my words come January 27th!