The iPad will very likely be getting a retina display, at least I hope. The rumour of a "new display technology" could be it, I hope it is because it's exactly what I want. You should all know that the only resolution possible that is greater than what it is now is 2048x1536, which is exactly double it's current 1024x768 resolution.
There are two reasons it can't be increased (unless in an increment of its original resolution):
1) If the resolution was to be increased by anything but an increment of its original resolution it wouldn't be able to scale properly like the iPhone 4 does. An example: let's say the resolution was 1536x1152 (1.5x current resolution), a control with uneven dimensions would result in graphic problems, say you had a button that was 101x101 pixels, it would be scaled to 151.5x151.5 which just can't happen.
2) If they were to change the resolution to say 1536x1152 (not scaling like iPhone 4), it would result in more work for the developer as they'd need to support the interface for iPad 1, and iPad 2. Currently with the iPhone, all you do is make your app and supply HD images, iOS automatically scales the app up on the iPhone 4, I really don't see Apple putting more work on iPad developers, they didn't with the iPhone 4 after all.