Or you can make your own out of a Weatherpack 4-wire connector.
I'm assuming that you only need the NSS and backup lamp functions? If so you only need the two Black w/red wires, and the two Red w/blue wires anyway.
I even do that Weatherpack conversion on stock C4's when doing the whole chassis re-wire. Nothing wrong with the stock ones of course, but the new ones look and work even better.
The down side is that you have to do it anytime you change the switch. But even with the old C4 variety, they don't fail that often.
Paul