I've never seen a real one but the idea of making one up using the standard wheelbase certainly is interesting.
I have discussed it at length with a friend of mine and it's something that may eventually come to fruition...when we have oodles of spare cash.
It surely would cause a stir at any MB meeting especially if it were to have a 350 mated to a 5-speed box, 15" Bundts or steel wheels & hubcaps, and not forgetting...a sunroof!