Noodles,

One way would/could be to use star-os as the gateway/auth system then your flatmates could be ratelimited dowe to 1kb/s I did this for kickes just to see if it works and it works well. You ratelimit depending on the users login.

There are other altenatives but this is a "Boxed Solution" and works.

This will work both for Wireless and Wired clients.