Yes!

There's one issue I hadn't thought of, though, and it isn't made clear in the Engadget article (and I'm not reading the press release - I'm sleepy enough already and I don't have 30 minutes here). Naturally, the Previews can't act as DVRs, and I understand that, but does this mean that they also can't timeshift?

I don't know what I thought would happen. I guess I thought the Preview might use whatever buffer you'd get from the Q, so you'd be able to pause or rewind/replay, but if I can't do any of that then unless the Preview box costs $50-100 and creates no increase in the Tivo service fee, there's no chance I'm picking one up.

A Tivo without timeshifting would be a sad sight indeed!