Thanks, Tom. Even if the hubs aren't identical, I would think that the spoke flange diameter would be the same, thus the 18" rim and spokes from the UCE would work. I know it's unusual to change the rear to an 18", but I'm building a '98 Bullet into an off road trials/trail bike with a 21" on the front and would like to run a 4.00X18 trials tire on the rear. I did find a Shinko trials tire in 3.50X19, so that may suffice. As for trying to use the UCE rim and spokes, I'm just trying to find an option to the high cost of Buchanan's parts and figured the OEM parts may be cheaper.
Bob