The nitro outdoor offroad track here in Denver put in a container for a drivers stand this year, here is a link to a pic of the stand.
I havent had any glitching problems since it's been up. The owner (Ross) is very active on the forum there too, if you send him a PM he should get back to you in no time.
The other track that i can think of is Arcor in Albuquerque
, where the Mod Nats were last year. They have a metal roof on the stand and a chain link fence surrounding the entire track, but i have never had any glitching problems there. I dont see any pics on their new site, but they now have a message board. hope that helps