No info yet!
I'm the last one to pour cold water on peoples ideas, but (you knew that one was coming....)I can't see how you are going to do it, I have just had a quick measure up and at over 1 liter the pistons will be so close to each other that there will be virtually no barrel left between them, I guess you could go 950 cc with siamised barrels and do the rest with the stroke, but 1600cc, I would love to be proved wrong.
Now if you were talking V twin then no problem, I would love to be proved wrong, tell us more....