erynnElo won't be coming back anytime soon. Couple of reasons: The way elo is implemented didn't account for people's skill on different classes. Depending on what time you play, you may have an inflated (or deflated?) elo that isn't representative of your actual skill (again, the way it is implemented isn't ideal) and the last reason, which is the actual real reason, is that elo calculations absolutely destroy the site and it is currently being held together with duct tape and tears. Bringing back elo is not an option until the underlying issues are fixed with the site and I can't tell you when that will be.....
If you're looking for more contributors, I'd be happy to help with the site (in general, not related to implementing elo).
Somewhat related, but has there been consideration given to open sourcing it again?