Nearly 14 inches tall, 17.5 inches wide, and using some 10 square feet of plywood, this V-twin is inspired by the thundering Harley Davidson (R) engine from the late 50's. Features a genuine rod and fork connecting rod arrangement, four separate functioning cams, and authentic valve action. See the Kickstarter for videos and details. You may download the assembly instructions here. (Note - these still have a few typos, and should be printed at 50% scale.)
Price - $150 per kit.
A video tour of the Assembly Manual