If you don't have ethernet run to your STB location, then consider a Powerline Interface. I have used them and they go up to 80mbps. More than what your ISP connection is. You just plug one in by your router, and others at each location where you want access.
Still, about the PQ. If the Video was streaming, then yes I would agree that better PQ would be a pipe dream. But if the VOD content is a simple File Transfer, then the MPEG encoding would have had to have been done in realtime (like a dbs or streaming feeds) so it has the chance of looking like a DVD.
Thats my hope anyway.