Looks to be a Ford style solenoid with some wiring. About the only thing special is the tab that "jumps" the solenoid on the starter. I think you could piece together a system for the cost of that one.
The main reason I don't like that style setup is, you still have the solenoid on the starter. Which can still get heat soaked. I think the main reason people switch over to the Ford style is they think it will help this. While I won't argue that it doesnt help some...there are better solutions. Usually the cables are replaced when this is added, and that was all that was really needed.
A better fix would be a heat shield or a mini starter.