It has been done. I'll be building a wheel soon with an AV89 reproduction hub. The only thing is it requires a french thread size freewheel and the reviews on the freewheels are hit and miss. Also the quality of sprockets are not very nice, some have warping from plating or something but they have warp on them. Nothing is ever easy in this hobby haha.
Hey, thanks for posting that link. I have a moby in my shop and I think it wants to donate a few parts to my next build. I was wracking my brain trying to figure how to get a good brake and two sprockets all on one wheel.