It just came to me in a flash (but not with Flash, because that would make Steve mad). Apple’s in the hardware business, and the tablet is not a standalone device, so you need something to connect it to. If you have a home machine and a carry-around tablet, then you don’t want a laptop, you want an all-in-one desktop. An iMac. Hence the name for the tablet:

iTosh

“iMac and iTosh”, or perhaps, “I Mac and Tosh”.