I dunno whether this will help at all, but I bought a repop 5.75" light from Flyrite Choppers last year that looks identical to that one, including the positioner ring. They no longer stock that light, but maybe Jason can point you at the maker.
http://flyritechoppers.com/
Whole light cost me $30 I think.
Doc
http://flyritechoppers.com/
Whole light cost me $30 I think.
Doc