Does anyone have any suggestions for a source of 1/72 scale wheels for a M123 scratchbuild that I'd like to do? I can't find anything with a similiar size and tread pattern for something of that era.

The size and tread pattern are the same as on the M25 Dragon Wagon tank transporter. The wheels are different though. You could probably get away with the Academy 1/72 Dragon Wagon wheels/tires.

I used the tires off a Dragon Wagon and put them on commercial wheels for my 1/35 version. I later replaced them with Tank Workshop wheels

These may be an option too.

1/72 Dragon Wagon wheels

Thanks for the ideas Gino. After you mentioned that I vaguely remembered some of those discussions, so I looked them up. I'll probably use a set of M26 wheels and convert the rims. I'm attempting to convert a 1/72 M35 to a M52. So far its going well and got me pumped up to expand to the heavy haulers for the next project.