I have been calling around trying to find someone that can replace tires for when the time comes for my 47, seems like I may be out of luck. Fclaridge what is your adapter pattern is it just custom to what you wanted or did they use something that is existing. I noticed the stock lugs are 5 bolt so is it a 5-10 lug conversion that you are using, just kinda trying to wrap my head around all of this.
Seems that there is not a direct replacement wheel out there for these trucks so might as well go with the 22.5 wheels and radial tires.
My bolt pattern is the 10 on 7.25 with a 5.25 bore. It is the 5-10 lug set up. That bolt pattern is also used in some modern trucks, but the adapters are made to order and I am sure yours could be made too. What is your pattern? I could ask the guy that made mine and see what he says. Then from there just get modern semi truck 22.5s and put on some 22.5 tires and bolt it on your truck.