Oddball is your best bet. Elmer's has some but I'm not too impressed with the quality. Local pickup is going to be limited since the demand isn't there - high price tag and high maintenance requirements.
When I am going to get some online, I'll either use Discus Hans or Carey Strong in Michigan.
Speaking of which - Discus Hans is going to be giving a talk at the next Greater Pittsburgh Aquarium Society meeting:
www.gpasi.org
I'm not sure if he's going to bring down fish for sale, but you can contact him. (I believe Oddball gets their discus from his stock).