Actually, a number of years ago Revell released a kit of the USS Yorktown CV-5 and it was 1/570 scale if I remember correctly. It was also reboxed and released as Hornet CV-8. Each were reissued not too long ago, and either could be converted into Enterprise (Nautilus Models makes a resin island conversion set)
Their original cost was under $20. You could probably find either of those kits fairly easily at hobby shops, swap meets or E-bay.
Revell also made an Enterprise (CVN-65) years ago, but I haven't seen it in ages. Can't recall the scale. Good luck with your search.
Paul
Paul
"A man's GOT to know his limitations."