Python and pyqt based chat application

I am looking for a python 2.7 and pyqt based chat application. I don't mind if you use free libraries but please use as few as possible. The application will be used on a network that is completely blocked off from the internet so the application should not need a internet connection. The application will run on windows. It will use your windows user name as your login name, so there is no way to change your user name. The first time the application is run it will ask you to give it a password to use and from then on it will need that password to log in. It will have group chat as well as private chat tabs for each user logged in. The application needs to be as simply written as possible because we will be adding on to it and modifying it. features: * Written in pyqt (QT creator) and python 2.7. We will be asking for the QT creator .ui files. * Uses the windows user name as the user name in the application. * has group chat as well as private messaging. * There should be a growl popup or other type of popup when you get a private message. * Audible noise when you get a private chat. * Private chat notifications can be turned off in settings. * Does not need to be connected to the internet * I am expecting a server script and a client script * Settings should let you change the server location ip * In group chat each user should have a different color * It should use a minimal amount of cpu processes * It should be low on network usage. * Code should be simple and well commented * There is a user list that shows the people logged in to the chat * Double clicking on a user in the user list will bring them up in a private chat XMPP seems to be a popular library to use, maybe that is the best one. I am including some screenshots of what the UI should look like. On the main window the private chats will go in new tabs that are next to the main group-chat tab. On the very left is the list of users currently logged in. Overall this is a pretty basic chat application. Most important it needs to be well written and stable.