I have heard of that in the past as well but dont think it would be achievable. there are too many water channels and internal webs to weld successfully . and with the availability of cnc porting machines becoming more common its probably easier to go that way with a standard head. But if you want to go all out why not do some research on motorcycle heads and see if you can match the bore spacing with say a suzuki huabusa twin cam head and mount that on a aseries block , that would be a good project!