I recall in Oblivion there was a save game issue where once you hit 1000 saves, you couldn't save anymore. I think it had to do with there only being enough digits or something for the saves, so that it tries to reset at 1000 but it can't, rendering you unable to save after that point?
I'm not sure what the cause is, but does this carry over to Skyrim? (as in, does it not allow you to save after the 1000th save?) I have about 600 or so now and was wondering what I can do to avoid this should I ever reach 1000.