Innovation does it on their military engines. They have a very proven robust system with good packaging. Monitor Marine Products has nice systems and suspect Mr Cool would be a good resource but I have no personal experience with his products.
Steve

No outlets on the back of the head, we changed some holes in the head gaskets to put more water back there. Another benefit of the closed cooling is constant pressure in the block and solid - not aerated water.

I hate rubber hose in the bilge. If you use the wire reenforced stuff the wire eventually rusts and the cut ends are always trying to bite