Rob Kool in the UK breeds them, but I realize that does you know good here in the US lol.
The only two I can remember seeing in the US both have really old sites that are not updated, but I suppose you could shoot them an email and see. If they no longer breed them they may be able to tell you someone that does. http://www.inlandreptile.com/yunnan%20beauty.html http://www.kingsnake.com/windingcreek/yunnan.html
I do recall seeing someone on this forum with yunnan beauties, maybe you could ask them where they got the snakes.
I am surprised you don't see more in the hobby. In the wild yunannensis easily covers the most range.
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