The fall auction is coming up, I bet if you find any Killie fish at the auction you can ask around a bit and find out who breeds them. I have seed them there in the past. That is how I found Larry Brown, who has a ton of very nice rainbow species that are hard to find.
There is a small killi fish club in Colorado. Edd Kray is one person you might track down. Neptunes sometimes has a few pairs. CAS had a talk on Killifish in June. Lots of killi fish in Colorado. Always some at the auctions.