Not widely available in the UK but used by all in the Nordic countries as its widely accepted that children travelling rearward facing are better protected in an accident situation.
Britax rear facing group 1 car seats, Multi Tech, Max-Way and Max-Fix models
BeSafe Rearfacing Car Seats Rearfacing is said to be 5 times safer than forward facing, and BeSafe are one of the original companies behind rearward facing car seats.