We at Whoooz! have a live development server running on a separate domain. On that one we develop all our EE sites. Customers can follow all our work on at any time and they love that. Customers can log in to our main site and follow all project related stuff like new design proposals, timesheets, docs and they can upload stuff we need. There is also a list of todo’s.
We put a lot of energy in creating this project environment (all build with EE and some customized Jquery), but it saves us a lot of project communication.