A British bookmaker has opened talks over a potential joint venture with Penn National, as  a William Hill US expansion becomes more likely. Hills has already made major moves in the post-PASPA era and is currently running sports betting operations in Nevada, Delaware and New Jersey, as well as a race book in Iowa. The firm is also working with IGT for the Rhode Island Sports Betting RFP. On Friday, William Hill chief executive Philip Bowcock revealed in an earnings call that the bookmaker has also signed sports betting deals with 11 casinos in Mississippi and a casino in West…