You could try What Price Glory http://whatpriceglory.com
They do a B-3 which is a bit more accurate than your average 'mall jacket' but doesn't cost the Earth.It isn't quite up to the top-end repros, but it doesn't look too bad-not seen one in the flesh mind you. Also keep an eye on Aero's sale page-they sometimes get in a batch of cheap sheepskin which they make a run of lower-priced jackets from. Or there's US Authentic, but I can't comment on their stuff as I have no experience with them. Or, of course, there's E-Bay. Good Luck!