We’re filing this one in the “interesting but doesn’t mean much” category. Apple sometime last year trasferred the “TabletMac” trademark from Axitron who make those Modbooks out of MacBooks. Keep in mind that Apple protects its trademarks pretty over-zealously. For instance, it made the iPodRip developer change is name to iRip because apparantly Apple owns the “Pod” name.
By now, (for better or worse) we’re pretty sure Apple’s tablet will be based on the iPod OS software. Therefore, TabletMac is only being protected to eliminate confusion over Apple’s Mac brand.