I think a UK Superbowl isent going to be far away. With the notion of so much happening in the UK in the oneies (2010-2019)
So far (let me know if i forget any)
2010 - Ryder Cup in Newport Confirmed
2010 - World Lacrosse Championship in Manchester Confirmed
2010 - Women's Rugby World Cup in London Confirmed
2010 - ATP World Tour Finals in London Confirmed
2011 - International Children's Games in Lanarkshire Confirmed
2011 - ATP World Tour Finals in London Confirmed
2011 - Champions League Final in London Confirmed
2012 - Summer Olympics in London Confirmed
2012 - ATP World Tour Finals in London Confirmed
2013 - Rugby League World Cup in United Kingdom Confirmed
2013 - Super Bowl XLVII in London Denied
2013 - Super Bowl XLVIII in London Bidding
2014 - Commonwealth Games in Glasgow Confirmed
2014 - Ryder Cup at Gleneagles Confirmed
2015 - Rugby World Cup in England Confirmed
2018 - FIFA World Cup in England Bidding
2018 - Commonwealth Games in Cardiff, Sheffield or Liverpool Bidding
2019 - Cricket World Cup in England - Confirmed
(yes i know only americans are concerned about the summer olympics and maybe the soccer but its alot of stuff going on)
So unless the world gets UK fatigue I think the Superbowl in 2018 or 2019 would make it a very impressive decade for the UK for sports