well you can put an epiphany frame on an ion so why not the other way around? btw, the trigger screw is a size bigger on the epiphany than on the ion so you might need to get an ion trigger. also, the magnetic trigger on the epiphany is just smidge too wide for the ion frame (at least mine was). my recommendation is to get an ion trigger to go with the ion frame. also, if i remember correctly, the frame screws on the epiphany were different lengths than those on the ion, although, the same size.
and as "proof", my ion with epiphany frame.