[Snowtractor]

Having worked a couple years in the plastics business I would wager a fair chunk of change that the moulds for these tires/tyres are sitting on a shelf in a room with dozens and dozens of other moulds. The mould cost so much to make in the beginning, why throw them out later and they do not take up much room.
So a sleuth should be able to track them down whether they were sold or not. Once located there are several injection moulding companies in southern Ontario that do small runs, if you have your own mould, on a per- pcs or lot basis.
These companies will make specialty moulds also, but they are damnable expensive.
Sean