Back in 1992, I had a Duo 230. It was about the size of my Macbook but with a much smaller screen. At the time, it was significantly smaller than other portable computers and perhaps 1/3 the weight.
Size matters, and in the minds of most laptop users (especially women): smaller is better (whew!)
I can see Apple giving us another small computer. Although it’s unlikely, I sure would like to see it have a dock like the Duo 230 did (with the Duo, you had a laptop but when you got home, you’d insert it into a dock much as you insert a VHS tape into a video recorder. It would get sucked into the desktop dock and voilá — instant desktop computer with full monitor and everything). I think the dock concept is unlikely, but would sure be cool.
I also suspect that a small computer like this will initially be optimized for data consumption such as reading a book. It may be usable for regular computing tasks, but I really think it would be a bigger version of the iPod Touch — and I think that might be the real reason Apple is opening up development on the iPod Touch/iPhone platform. Once those applications start appearing, such a device would become quite popular IMHO.
But that’s pure speculation on my part. It’s not what the rumors are, it’s just what I would do if I was in charge of Apple. Which I’m not. And so far they’ve done all right without me (except for the later Sculley/Spindler/Amelio years, of course).
The Duo didn’t have an internal floppy drive, and I suspect that any new sub-compact from Apple won’t have an internal DVD drive. They may not even use a standard hard drive — imagine solid state storage instead (a stack of SD card equivalents!). So there’s my prediction (and though I wish, I don’t expect the VCR thingy). One more thing: the trackpad will have multi-touch capability.