Well, I did just that on a friend's car, it was supposed to be a temporary fix so we can move the car under it's own power but, he could'nt resist and whent out for a road test, he said he kicked the s*it out of it and everything held fine.
I took two industrial pulleys of unknown origin that he had laying around, I took those cause they were thick and allready circular and about 4" diam.
Then I took 2 pieces of angle iron, mesured by eye, ground the corner flat so I could put them back to back to form a simetrical + shape, welded them together, with one pulley at each end, drilled both pulleys according to the diff/shaft patern and hooked everything together.