...with British betting companies. I can't check the exact odds right now because work blocks those sites, but off the top of my head the odds were:
Kipsang 2:1
Farah 3:1
Kebede 4:1
E. Mutai 7:1
G. Mutai 8:1
Jelian 10:1
In my opinion Farah will not win, and it seems like pretty tasty odds for some others with a better chance. I've never bet online before, but I might just throw some money down on G. Mutai.