For jobs that size i'd recommend a 6" chuck. No way will you get a new machine for $15,000 though. A place I worked bought a brand new 12" chucker and it was about £60,000. Thats pounds not dollars. For your price range i'd go for one about 2-3 years old. Just like cars they lose a lot in price during the first few years so second hand will be best.
IMO, Mori Seiki make the best machines but you will pay big for one of these. Plenty other companies make decent machines though and at a cheaper price. Daewoo, Yang and Nakamura to name but three.