Taking the alfine off the commuter but would like to reuse the nice 24h Shimano rim. Cant seem to find one, just for my commuter so cheap is good.

DT Swiss 240s is the only one I can think of.

In other words, much cheaper and less hassle to buy a new 32H wheel already built!

Just use a 32 or 36 and miss some spoke holes.

The wheel is 700c Shimano but that size wheel with disc ready hubs is pretty thin on the ground. I guess it might be easier to get a cheap 29er disc wheel, I understand wide 700c tyres will work as the rim diameter is the same?