QT movie store may be doable now, but that doesn't mean its marketable now. The cost of supporting it at this stage would far outweigh any revenue to be made. However, that said, Apple has often tried to be the first with a new technology even when they know its not profitable, simply so they can have the market.
XServe: A G5 X-Serve sounds like a reasonable next step. I doubt we'll see blades, though, because Apple's philosophy is strongly against making products that require special, expert handling. The X-Serve is a set and forget machine that any halfway competent network administrator could set up, even without server hardware experience. I think they'll keep it that way.
As for iOffice, this seems like a realistic possibility. Of course, we'll have to wait for the "just one more thing" eh?