Well reluctant to say because Ive been chastised before and may be deleted but Shopsabre has a 30x40 machine, ball screw, 600ipm, .001 accuracy machine, and Im sure Camaster, as well as Gary Campbell can offer their own advice as well as options on many other.
Sorry, but getting into machine specifics, brands, and so on seems to be a really touchy subject here. You even see small options from companies like velox though I have no idea about the specs and am always suspect with retailer based options.