Here in New England, we not only have NEMA and NEMA Lites, we have the Dirt Midget Assn, which is affiliated with USAC. They had about 20 cars most nights this year, and it looks like more are coming next year. One of their young members said he has about $6000 in his car, and it is quite competitive. From my point of view, they sound much better than minisprints.
http://dmaracing.org/