I'm pretty sure there would be rich pickings on betfair, as there will be a more varied set of odds on offer and this would presumably get around the issue of moving money around and associated charges, although they take a slice of the action, but not sure how much.
If you did have a big pile of cash then picking up on a couple of high return arbitrages every now and then would be very profitable....but I don't have a large pile of cash
On to the next grand money making scheme then....