The Keihin carbs are available brand new or in good used condition on Ebay all the time. They're also common to a bunch of riceburner bikes. I'm thinking about using three of the diaphragm-piston carbs designed for a bike with approximately the same displacement as one cylinder of an inline six, since the firing order of stovebolt engines has only one cylinder at a time being supplied by any particular port. That's why running dual carbs is such a boneheaded stupid idea. With one carb per port, the size of the carb can be tailored exactly to a specific engine displacement and RPM. Then the only gremlin to battle is keeping all three carbs synchronized. The upside is the ability to impress the mouth breathers at a car show who don't have the common sense to pour pee out of a boot with printed instructions on the heel!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!