To me, it looks like a sectioned VW weber center, possibly set into a large, thick-walled tube for a plenum and welded runners to the factory elbows. Can't tell from the pics but looks like the coolant must flow into and out of the plenum floor area.
If you've better pics, I'd like to add it to my site. Very interesting!
Has been my experience that heating a manifold for a 4-cylinder Goldwing is done for a reason seperate from the issue of carburetor icing.
In heating the manifold, the heated interior walls of the manifold create a "boundary layer" of air that acts as a cushion of sorts for the flowing air/fuel mixture to ride on as it makes its way to the combustion chamber. Done effectively, the intake charge never touches the manifold. If a manifold is cold, the possibillity exists for the intake charge to collect on the interior walls of the manifold. In doing this, the air/fuel vapor collects upon itself enough to reform into a liquid, break free from itself and enter the combustion chamber in the form of droplets, creating a overly rich condition. Think of two opposing magnets. They repel each other. This could be viewed as the heated manifolds "boundry layer" of warm, cushiony air repelling the cold intake charge as it travels through the tract. With a cold manifold, one pole is reversed and attraction begins. A bit over-simplified but visualize it terms of magnetism and you get the idea.
With a warm, heated manifold the intake charge through the carbuetors venturi sees none of this boundary layer in the manifold yet. The air and fuel are mixed in the carburetor and as it, the atomized air/fuel charge, passes through the throttle valve, the new vapor is extremely cold.Cold enough that it could turn to ice. Air temperature and humidity play a key role in "carb icing" at this point. If the humidity is high enough, and at any temp below about 70 degrees F, then icing of the mixture as it passes through the venturi may happen. This happens before the manifold, before entry into the manifold. At very low temperatures (0 - 10 degrees f) carburetor icing may happen regardless of humidity. There's always enough moisture in the air at those very low temps for it to happen.
Combine carburetor icing with a unheated manifold and many will stay parked in the garage.
Combat carburetor icing? Yes, it is possible. Heat either one or both; Fuel or Air. Pre-heating the intake air is the most common. Light aircraft require carb heat. Usually pulled from the exhausts waste heat. We can do this on our bikes, and pull it from the radiator as well. Pre-heat the fuel?... Imagine, a 12V water heater element in your fuel tank. Heating either the fuel or the air will help combat carburetor icing. Heating the carburetor body is also a option, but not a very effective on in my opinion. Heat-transfer from the heated manifold to the carburetor body does little to help the carburetors body gain enough heat to be effective in my experience. Pre-heating both fuel and air are 100% effective in my experience with a GL1000 down to -16 degrees F.
Carb Ice and a Heated Manifold are really two different subjects that are ancillary to each other from a induction system point of view.
As a side-note - I've found that a single-barrel carb is better than a two-barrel in that; the smaller primary venturi of most two-barrel carburetors (compared against the larger venturi of a single-barrel carburetor with a equivelant total CFM rating) provides for more oppurtunity of carburetor ice to form due to the higher speed and velocity of the mixture passing through its smaller venturi opening. Two-barrel in the warm, single-barrel in the cold. That's my conclusion unless pre-heating the air or the fuel with a two-barrel is done ...for the reasons noted above.