Well, I went to my local MA today after deciding on WCMM after all. However, next to the tank, they had some yellow WCMM that they had found mixed in with the T. albonubes from a recent shipment from Vietnam. Having recently stumbled across this Amazonas article, I was pretty sure they were Tanichthys kuehnei so 12 of these came home with me. I'll grab some photos once they've settled.