I have Scoreloop plug&play solution is ready for both Android and iOS. It is PAID solution. Let me know if you need it.
I am writing facebook & Twitter plugin meanwhile. Almost done with it. It will be published over this weekend. It’s going to be FREE. Watch https://www.facebook.com/Ezibyte or follow on twitter https://twitter.com/ezibyte
Both Scoreloop and Social Networking Plugin (Facebook, Twitter, Internet Connection and Email) will work with Android and iOS with common code.