A 784cc V-twin-twin?
Someone made a working V-triple Harley: anything's possible if you throw enough time, money, and elbow grease at it.
You'd have to get a crankshaft made from scratch and make a custom ignition system, but that's easy peasy after fabricating the crankcase....
Actually you know... you might be able to use the stock cams and ignitions if the crank were made to match. Set the timing for the second set of cylinders 360 behind the first maybe.