There was a story doing the rounds last year that Setanta had proposed an HD sports channel but Sky had refused to give it carriage, making it uneconomic to run in the UK (Virgin not having sufficient enough customers to make it viable as the sole carrier).
Strangely enough, there's a thread over on Digital Spy
here that also starts with the Setanta HD vans being spotted. Turns out they shoot a number of games in HD for the overseas market, but not for home consumption. Yet.