I interviewed Brian Ray of the Paul McCartney band. He played a JCS, an SG Bass - if I remember correct - and the last years you could see him with a black Epiphone long scale EB3 with white MOP guard, to match his signature SG guitar. And a white one with black. He told me he liked the SG looks, but he wanted a long scale for a tighter sound.
He told it was made by the Epiphone Custom Shop. I asked if such a thing excisted, but then he told me Gibson just orders some bare bones EB-3 bodies and thet fully equip them with USA pickups, hardware and electronics and paint them. So I guess it's the Gibson CS working on some special stuff now and then. If you play in Macca's band they will do a lot to satisfy you.