A simple socks4/socks4a/socks5 server written in C++/Qt. I run/test it mainly on Windows 7 with MSVC2010, but it should work in any place Qt does with minimal issues.
Make it so that it can be optional or mandatory. Implement it using the already-existing state pattern architecture. Put it as a state before the current initial state.
Will have to be integrated with some kind of database or config file.
SocksSession will be used to group multiple connections from a certain user. Bandwidth tracking and throttling will then be able to be applied session-wide.