80/20 (fractional) parallel mating plug

This is a small, friction-fit plug that mates sections of 80/20 profile together in parallel.
See 8020inc.net for more information on 80/20.
Hopefully, the photos will make the application clear - while 80/20 has a whole galaxy of different types of couplers and fasteners, I wasn't able to find anything that mates profiles that are flush up against each other.