Add an easy-to-use way of setting up centralised user management

It would be great to be easily able to set up a small number of computers with centralised user management and shared home directories. I don't mean a complicated system of managing tens or hundreds computers but something that would work for five or ten computers in a small lab or at home.

A preferable method of presenting this option to user would be a simple applet with two or so buttons. One for turning the machine you're using to a server and another one to join an already available workgroup by entering server's ip or domain name etc.