I share your concern. I have this creeping feeling that MWSF will be the launch point for 2nd gen iPod Minis, with 6 or 8 gig HDs and a color screen.
That said, I just bought a Mini this week. 😀 I couldn't wait any longer. I decided I'm going to sell it the minute the new ones come out (or better yet, the minute rumors of a new one start up). 😉
Regular iPods are updated every 6-9 months. In January, it will be ~11 months since Minis first went on sale. I think 11 months is about the time when you need to update a product to keep it competitive. Also, if they're introduced at MWSF, you have the "1-year anniversary" factor, which would just be cute. 🙂
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EDIT: Come to think of it, I'm not sure anyone yet makes an 8 gig HD that would fit in the Mini. So, 6 gig might be the max HD size, I don't know.