in reply to using jabber for RPC or inter-server-communication
you could use a range of client/servers, e.g. mysql database or postgres if you want triggers, RPC, email, FTP, news, etc. You should think about the characteristics of the connection you want and try to match that to an existing protocol (for the sake of re-use and not having to write your own client/server). That crucial answer will steer you in a particular direction. I'm not sure that a chat server/client is particularly well suited to the transmission of commands, as on a chat session it may not be a big deal if a character gets lost here or there--commands and their parameters must be 100% delivered and executed or 0%. oh well, that's my addition to your salsa.