Even though it's been known that U2 was doing preliminary work on booking a North American summer stadium tour, the word in recent weeks is that it probably is not going to happen.
The Edge made comments to Billboard when he was in New Orleans on November 17th that indicates that they know they could play a lot more shows in North America and Europe but they would not like to push it too far.
Also, fans have got indications from crew members that the tour is ending in April. One fan here on Interference was able to get a date of April 14th and the location of Honolulu as being the final show of the tour.