Aus. Aviation had an article in October issue that says that the 717 orders are decreasing, and that the production line will slow down next year (would have to check the article again to get numbers).
Add to that the fact that the 717 line has not hit targetted production numbers yet at all, and i think it is safe to say that it is probably going to shut down within the next two years.
Pity, as its a very economic aircraft, quiet and comfy. A better run of luck and it might have followed in the 73's footsteps.