We should be getting some decent bodyboard bags in at
http://www.factory7.co.za within the next few weeks from Island Style. They have always made some good covers at decent prices which provide the protection you need for throwing your boards on the plane.
You can take a look at some of the covers at
http://www.islandstyle.co.za.
If you're still in the UK, then try Rhino boardbags ... I had quad of theirs for years. You can pick them up from various stores but try
http://www.bodyboardhq.co.uk/html/newsh ... DBAGS.html
I would give them a call though to check what straps the bag carries. Mine had backpack style straps but no shoulder strap which makes it a bit difficult when you're carrying a backpack around too.