This type of stadium would take 3 flies in one smack. Football field, running track, and stadium all in one map. These are common places people go to train with their quads.
Yes, it's a good idea to get 3 in 1. (Although I don't personally think the running track would be so fun to race in it's own, you know, with these long straight stretches and wide turns).
Just wanted to add some interest to this map type. A flat and semi-small area with gates/posts would be fairly close to what a lot of people are racing. The pitch itself is what is interesting to me, not the surrounding running track/stands.