I thought all your constructors might like to know about the Roar Engine. Essentially it is a back end for multiplayer social games and rpg's. It handles everything from inventories and currencies to achievements and magic items:
At the moment I am considering writing my own middleware for it that gives simple responses which construct can handle, however when there is some sort of native json/xml parsing it should be a doddle to work with.
@digimonk, would love to see integration but we only have 2 programmers and we're already incredibly busy. I'd suggest trying the SDK - if you get stuck make a post in our SDK forum and we should be able to lend a helping hand.