Hi Steve,
I have the same query. Have you had any replies?
I've just bought a 2013 B Max Titanium and the Ford garage says the only way to fit roof bars is with a retro fit rails system from Ford that then takes cross bars - cost £650 fitted!! Needless to say I am looking into tow bar options.
Before go for a tow bar (and sell my full Thule roof set including three bike carriers from my Ford Focus) I am trying to get a definitive answer to your question - are there any market roof rack/carrier systems available?
I may try this question on one of the other forums as well.
Jan