I always assumed there were no black libertarians. I thought only a white person could believe that there are no significant differences in available opportunities for different people, and without that assumption, the moral argument for libertarianism collapses. Thanks for informing me about Elder and the others. I will check them out. I think libertarianism is a disaster both conceptually and empirically, and I say this as someone who was once very sympathetic to it. I'm still sympathetic to something some people call "left-libertarianism. This lecture is the summary of my thought and research on the topic. You might enjoy it.

https://www.academia.edu/5393180/A_Critique_of_Libertarianism