Most large metro areas have a shop that does that kind of work. I used a company here in Fresno to get the outer rims from for a set that I did several years ago. 15x10 was hard for them to get so they had to get them from Wheel Vintiques (who won't sell parts to the general public). I paid $35/each for the rims (so you know that W.V. probably paid $15 or less).

Check your local yellow pages.