I spoke to someone who used to build rotary mod kits on this board. He's not making them any more (actually, I think he's moved on from the hobby), but he was able to find connectors online that will work. I bought a few from him and, while they work, they are not great. They slide on with a LOT of force and tend to bend the connector if I'm not EXTREMELY careful when removing them.
All I'm saying really is that they are available, but I don't know what size they are. Your best bet is to measure the distance between the pins very carefully and find something at Digikey or Mouser that matches. It's obviously a 13 pin connector, so you won't have a ton of choices.