I thought autosaved content was saved as cookies, but I'm not entirely sure. Even if it was saved on the servers, it shouldn't be too heavy on the band-width or the servers at all. Imagine you posted that post instead of autosaving it. Bam, saved forever. It shouldn't make a difference.

For the autosave function, you'd need a newer post editor, which to be honest, would be far from a bad idea. This thing we're using right now is REALLY old.