I've just made a start on building a trike based on a Reliant three wheeled car drive line.
I was thinking about doing all sorts of "retro" stuff with it, but frankly, I ain't that interested in trikes per se trikes. I kind of enjoy moaning about building them though...
Anyway, a bit of a hunt round round the workshop turned up a pair of 17" wheels off of some sort of daft and bicurious hot hatchback type thingy, and a set (actually 2 sets) of GT750 Kawasaki forks.
With the driveline pulled from the Reliant and the 17s nailed onto the the axle, I propped the motor and tranny up on a block and propped the front end up more or less where I think it ought to go.
To give you an idea, the block of the motor from the front motor plate to the bellhousing, is 13" long.
It's a 750cc, water cooled. fourbanger.