Kind of reminds me of the Stadium builder in Earl Weaver Baseball. We used to make some really crazy ballparks with that thing.
Seriously, I don't think any ballpark type builder/generator would make anything that would come close to the detail as some of the user made ballparks. However, a stadium builder might look something like this:
http://archive.secondstory.com/proje...r-own-ballpark
Funny how one of the main developers was a guy named Matt Arnold... hmm....