Nu-brite is great, they have done dozens of wheels for me. they are just up the street from AirSpeed.
the 3 main companys that do this are.
Greens
Panther
Nu-Brite.
now you may want to grab a phone book and call around because im not sure if they all do Steel wheels. Nu-Brite specializes in Aluminum.
the process of doing a steel wheel is a bit different. i think with steel they cut out the face of the wheel and weld it into a new barrel.