Sky have a communal system that works with Sky+ - maybe they would upgrade it for free if you got a few neighbours to sign up too?
http://www.sky.com/portal/site/skyco...entid=10504703
---------- Post added at 13:25 ---------- Previous post was at 13:21 ----------
The other option if there is a spare port on the disk is to use
these to run two signals down one line. Bit expensive tho.