"is there anywhere I can get Sun Ra material other than the Evidence re-issues?"
Well, I don't know if this will help you out in Michigan, but on my last trip north I saw large collections of Ra (some 30 titles) in the Washington DC Tower Records and in the Princeton Record Exchange, Princeton NJ (the best used disk store not on Saturn). I presume the nearest Tower to you (Chicago?) would have a good selection.
Jon Meltzer Institute for Academic Technology, Durham, NC