I'm still super-curious about how they're going offer feedback from a virtual UI that's as good as the tactile feedback from a scroll-wheel.
Maybe it just won't be as good—it'll just be something of a trade-off. Great video, wireless capabilities, smart UI, and potential ebook reader... and somewhat less tactile feedback. But questions still linger. How do you protect the touch-sensitive screen? How do you operate it from your pocket, or w/o looking at it, by feel?
(Just as an aside, a neat ability with a virtual scrollwheel could be the ability to change its size, just by, say, dragging the divider between screen and wheel.)
A December introduction would be very unusual, but I could see it as slim possibility. They've left a new space in their lineup for a high-end iPod, and if they could get the models ready in time, I'm sure Apple would like nothing more than completely vaporize even the faintest buzz the 1G Zune might be able to summon up.