No one piece wheel exists with your bolt pattern, short of having custom wheels made using your centers mounted into new one piece rims. Your rims are called a Firestone RH. They were an industry standard from the early 1930s to late 1940s. I can believe that you would have trouble at the bigger tire shops. Just this week I learned that the shop I use(d) will no longer work on RHs. I'd suggest checking small towns around your area, big truck shops, and ag type shops that have been in business a long time. In my case the shop I've had work on my RHs was bought out by a chain operation that has now changed their policy. Below is the RH. Stu