Warner Bros kinda doesn't like fans of anything that isn't DC comics related. At least when it comes to DVD's. Sesame Workshop would be the company you'd have to twist the arms of... seems the distribution deal was mostly about Elmo DVD's since they're profitable. The Spoofs set shows there is a nod to old school or at least adult fans of the show, and that could very well mean we'd see more stuff like that in the future.
Other than that, amazon and iTunes or something like that has the older episodes... I really wish they'd find a way to put older episodes on hulu like SW does with The Electric Company.