I ended up getting an L shaped adapter like bill suggested. I have c clamp vise mount and use the Dyna King adjustable L adapter. It works with any vise with the standard diameter shaft.

In my case, I insert the adapter into the underside of the clamp and the vise jaws end up at about desktop height and swung out away from the table. Before I lowered the vise I had a lot of shoulder problems. Works great. The extension is adjustable so it can be used to set the vise over a wide range of heights.