Watch eBay for brackets and parts. You may be able to use the tensioner or pulleys off some other applications. The VS stuff is not as valuable as the VR components, so you still have a chance of finding some early aftermarket bracketsThe VS57 website has a classified section and photos of the old style brackets. Study how they moubted them on other cars
A few guys have built really nice looking brackets and pulleys themselves for their special applications.
A VS or SN(the newer versions like of fox mustangs) style blowers can still be rebuilt and parts are avaliable. Paradise Wheels in California is the source. The VR57/58 is a special blower and no new parts exist for rebuilding, without a complete internal conversion to the SN internals.
I would run a later SN(90-93) blower because they are still easliy avaliable, unless I you building a 57 Ford with an F-clone.
I used Franks Rice's parts to peice together a complete factory looking F-style motor using a converted VR57. It is fairly reliable, look svery correct and runs great.
If I was to build anything other than a F-code style car and original looks was not a concern I would choose the later SN 90, newer style paxton, vortec, or powerdyne blowers with rigid handmade aluminum brackets and pulleys.