It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.
I've had more than one set of A body 8 3/4 axles drilled and tapped for screw in studs to move and change the pattern to 5 on x 4.5 so we could use the stronger 1/2 inch studs and cheaper and easier to find wheels
I just had this done on a set of stock A-Body axles (8-3/4) at a guys shop that specializes in building custom rear ends.
With machining the axles for the screw in studs, installing new green bearings and drilling the drums it cost me $300.
