This could be scary but you said you have created a lightweight RPC server bitcoind, based on JPosse, I just looked at that code, it isn't RPC, it just returns JSON, this would not work with any existing software, kinda disappointment I could have really used this.
RPC just means
Remote Procedure Call so he wasn't lieing. You've probably confused RPC with XML-RPC which is the standard used in Bitcoin-QT.