Are you only wanting to go drw because of the dual front wheel hubs or because you want a dually?
You can take those dual wheel hubs and have the dually flange turned down.
This is my understanding. I've ran across a similar thread on pirate 4x4.
Hubs for the Chevy are also impossible to find. One of the threads detailed how the guy had his hubs turned down at a machine shop to go from drw to single.
Apparently once that flange is removed the hub is identical.
1991 k30 cclb 6.2l 4l80E
1986 k30 cclb 6.2 n/a th400 dually
1984 k30 cclb dually 6.2 banks turbo th400 gear vendor
1985 gmc suburban k20 banks 6.2 t400.