You know, there's a Thai seller on AB called Bettaprothailand that has some kois up. You might try emailing them and just seeing what they would sell you a sibling pair for. I only mention it because their bettas start at just $15 bid, and they have such an enormous file for their pictures that I doubt many people wait for it to load. (I have a very fast, liquid-cooled computer, and they load too slowly for me to stand.)
If you were able to get a pair you liked for a good-enough price, it would make up for the transshipping cost....