One solution I could see for this whole is it a legal FIRST part from a legal FIRST vendor issue would be for Outback (or whoever) to work out a deal with one of the existing FIRST legal vendors that market to the whole hobby robotics market. There are many existing vendors that serve the hobby robotics market but the one that comes to mind is
Robot Marketplace. It would seem to me that a reliable, cost effective, off the shelf, standard tread system and gearbox would be popular even outside the FIRST robotics world. If it is legal for FIRST teams to buy BattleTread or Colson wheels from Robot Marketplace then why not an off the shelf tank tread assembly (assuming it meets the cost limitations)? I feel the issue is more with a team and a machine shop trying to market a specific product to a limited number of teams. Companies like AndyMark and Banebots market products for robotics not specifically FIRST robotics.