The Nemrod solid bar manifolds are pretty cool as well- this one:
http://www.ebay.com/itm/WOW-Nemrod-3-4- ... 1c35859a7e
has both the center manifold port and another on the right post (diver's right when worn). Either the center port or the right post port can be shut down-and my understanding is that the gas from both tanks will be available at all times to either port even if the other port is shut off…it is not an isolation manifold like most available today-but I think that is fine for non-tech divers in most recreational diving situations (guessing that is most of us/most of the time here). This or the two-port Sherwood Selpac allows a redundant single-hose reg mounted on the second port…especially a vintage single hose reg.
Cheers, Tim