Yeah, Thunder, take hours out of your life to prove some niggling point to a guy you barely know on an internet forum!
You think some peer pressure from other largely anonymous strangers will help?
DO IT! DO IT! DO IT! [others join in]
Anyway. That resolution really isn't necessary for the subject, and it'd be a system killer to run. It doesn't improve anything to have it so... uber, and as was mentioned the tiled textures seem to give it rather ugly problems around the edges. A single texture of 2048xsomething would be plenty, I think, plus at the distances where you'd even be able to notice individual pixels people'd already be too busy going on about "WHAR IS TEH GRAVITIE" to notice the nice tex job on the planet.
It's a cool job, but really background stuff like planets is just there so people have a setting for the action- if people are going sightseeing in a shooter, you've probably done something wrong, and it's a pain in the processor to handle stuff like that- especially when people'll be wanting to spend that memory and ****e on things that actually have a real bearing on the game, like cruisers and bombers and Christ knows what shooting at you.