Nikon is expected to release a 24MP version of the D3 on December 1st. There also might be a hopped up version of the D700 as well, but who knows.
Stitching is a great way to capture static images, but if anything is moving, then you're out of luck. High resolution cameras make better large prints, but you lose things like low light performance, and speed of shooting. If you're going after flying eagles, you might be better off with a 12MP D3, than a 24MP D3x, as you're a lot likelier to actually capture the image with the smaller MP, faster camera.
David Buzzard