Yes, bull minnows are another common name for banded killifish. They are the same species, just different common/local names. Zett's is the only hatchery I am aware of that sells them in the east, or least that I have been able to find. As to whether they still sell them I cannot say. You would have to give them a ring. If they don't, I have a large number of them in my forage pond and can get you some if you would like. They were sourced from the Potomac River watershed originally and have been pond bred now for 6 years.
Male coloration
Female Coloration