Well an obvious but most likely overlooked item could be better battery life, how could they manage that? Ultra awesome energy efficient dual core A5 chip perhaps? 
1. MiniDisplayPort out - No, I don't think that will happen
2. 4X pixels to 1536 X 2048; same strategy involved in the iPhone 4 - No, Apple will not throw a high-res panel like that into a 10" form factor. Do panels like that even exist?
3. USB in - No, already a dock connector for that
4. Dock connector on one of the long sides - No
5. Mouse/curser support - Absolutely fricking not... Jailbreak if you want that (PS: it sucks)
6. Verizon option - Maybe
7. Expensive - Yes
1. Why not? This can lead to VGA, DVI, HDMI, and DisplayPort output..
1. MiniDisplayPort out - No, I don't think that will happen
2. 4X pixels to 1536 X 2048; same strategy involved in the iPhone 4 - No, Apple will not throw a high-res panel like that into a 10" form factor. Do panels like that even exist?
3. USB in - No, already a dock connector for that
4. Dock connector on one of the long sides - No
5. Mouse/curser support - Absolutely fricking not... Jailbreak if you want that (PS: it sucks)
6. Verizon option - Maybe
7. Expensive - Yes
I would love some better video output option (dare I say HDMI?), but I doubt Apple will go that way, especially since they want to transition into streaming media
I don't think apple will do retina display for the next ipad not because of not being able to source the high res display. The issue will be finding a low power graphics chip to drive the high res. I think apple will make the ipad a little bit smaller but keep the resolution. I guessing they'll shrink ipad to 5" screen which will make it pocketable. Also, camera will be there, both front front facing and back. More capacity, maybe like 128gb. Also, ipad will arrive on verizon before iPhone. I'm assuming AT&T only has exclusive on iPhone. Also, cloud storage will be introduce since you can produce more content on ipad.
I don't think the next upgrade will happen in September... Reason being we'll get iOS4 released around then, and I'd bet it has a few features that aren't included in the iPhone release. That will make of our already purchased ipads 'new' again... Enough to make us sly happy for another 6 months until a hardware refresh.
When that happens, it'll only be the most expected updates. Front facing camera, 512MB RAM, and MAYBE a higher resolution display. In my opinion the display is already great, but some may feel there is room for improvement on a relative basis. And either thinner / lighter with same battery life, or same thickness / weight with a few more hours of life.
Ha buy one here in england and get it shipped over![]()