There is a modular, modern, open source implementation of the BItcoin protocol with properties, e.g. remote wallet, you look for at bitcoingrant. It is Bits of Proof. A supported and hosted product launched at the BItcoin2013. 

You find the source at https://github.com/bitsofproof/supernode and supporting documentation at http://bitsofproof.com

Tamás Blummer