Tow hitch?

Anyone know where to pick up a hitch for a '70 Duster? I don't care if it is new or used. I would really prefer a Class II but even a Class I would get the job done. I just need to be able to pull a small 4x8 trailer to haul my dirt bikes around. I have only found a single Class I hitch but was hoping there were other options. Ebay has been no help.