What exactly are you looking for? new used? your title said frame/chassis,
I just wondered, I saw you were in Houston area,
If you are looking for a fixer-upper what about this, http://houston.craigslist.org/mcy/1430673248.html
I just bought this off craigslist for one of my son's B-day yesterday, paid 150.00, runs great
I think I saw another 50cc dirtbike, similar for same price.