James, Consider posting your question to the Studebaker Truck Talk Forum.They're a great bunch there and very informed and willing to help when it comes to Studebakers. <<< Ask me how I know....
I built my own for the 37 President coupe. If the knuckles have the same bolt pattern you could do the same. I used Geo Metro parts. If you want more information and a pattern for the caliper brackets let me know. Brakes work great. I do believe the President brakes are larger than Commander but the knuckle patterns might be the same.