A guy named Mike Ramsey in No. Car. used to make a fretless banjo-a "Chanterelle" I think-dunno if he's still making 'em, and they are prolly a lot more than $450.00-seen a few of his on Mandolin Bros. website. Anyway here's a link (maybe) or something you could copy and paste to check him out. Just curious as to why you want a fretless one?
http://ramseybanjos.com/