Then again, a 30" display is 2560x1600 and costs over $1000. Will they really get that many pixels in a 10" display and still keep the price around $500.
Physical dimension is a very large factor in LCD panel pricing, and a 10" panel is only 10-15% the size of a 30" panel. I wouldn't be surprised if Apple could get hi-res 10" panels for cheap, especially since they'll be ordering millions of those.
So if it's easier to pack 10MM subpixels into a 10" display, why do they sell 30" displays of that resolution and not 10" displays of that resolution?
I figure the high cost of 30" panels is due to the defect rate, which increases with number of pixels (which is why 1920x1200 displays cost about the same, regardless of whether they are 27" or 24"; same defect rate). And, I'd think it's easier to make a big working pixel that a small working pixel.
In conclusion, I highly doubt that the next iPad is going to have a screen of this resolution.
I'm going to go with "unlikely".