Just throwing this out there...
What I think would be cool would be an iPod Touch Pro (or whatever you want to call it) that's about 7 or 8" widescreen with Wi-Fi (a/b/n), a couple USB jacks, Bluetooth, a built in stand (no, I'm not kidding, I don't want to have to hold it upright when watching a movie on a plane), all the iPhone apps + a Mac-like Safari so I can watch flash and, here's the big kicker, work out a deal with AT&T (in the states) where you can choose from either, say, a bigger battery or an AT&T 3G card and if you get the 3G card as well as an iPhone (any kind) it'll be like $5 a month or something cheap. That would get people more likely to buy an iPhone if they were thinking about it but weren't sold on it but really want the "tablet" and would get a lot of people willing to shell out just $5 a month for 3G on their iPod Touch Pro who already own iPhones. 🙂
Yes, I know I'm dreaming but it's fun to dream!