It is an interesting idea, but given that it is a jet fighter, you have to wonder just who all those rear guns would be shooting at. An ME-210 or ME-410 is a different situation. Only the US did not have much in the way of enthusiasm for multi-seat fighters with aft facing guns. The Grumman FF-1 was one of the only US types ever produced and it led to the much more popular F2F and F3F series of single seaters.