When I was at Best Buy picking up my Evo, the guy next to me picking one up as well mentioned that he knew where there was a 4G signal in the Minneapolis area. He said it was the sole location and I am guessing it is a Test location of some sort. He couldn't reveal the location because he said he was under an NDA. (I told him he should anonymously geo-tag it so that we can all enjoy

-- he was mean and didn't seem amused and said that would probably violate the NDA...jerk)
My best guesses are some sort of important business area, or government building, but I have no idea where to even begin.
My question is for anyone that might have any good ideas. Where could this location be? Where are the typical test areas in these pre-4G cities?