Motorcycle engined cars are cool. High revving, light, fast, focussed. Not really the thing for the daily commute (unless you’re some sort of sports car masochist) but just the ticket for the weekend.
Recently Autoblog and Jalopnik have posted about the Suzuki-engined smart which is cool, if possibly a little moose-prone.
British company zcars will put a Hayabusa engine (and other kinds of bike engines, too) into just about anything. Check out their rear-drive mini, and twin-engined 4wd turbo-charged Ultima.
If that’s not enough, go to kneeslider, a motorcycle website, for their list of motorcycle engine powered cars.
Finally, my two favourites:
Fisher Sports Cars in the UK make the Fury and the Menace. The Fury is front-engined and will take just about any popular engine found in kit cars including the ubiquitious 4AGE but it will also take a ‘busa engine, complete with 6-speed sequential transmission. The Menace is the same idea but is bike-engine only and mid-engined. Unlike a Lotus 7, the Fury and Menace look like they were designed in the later half of the last century. The Fury in particular has a lot of Elfin MS8 Streamliner about it (or that should be the other way around) which is odd because I quite like the look of the Fury but the Streamliner looks overdone.
Grinnall cars make a bunch of weird stuff but my favourites of theirs are the Scorpion III and Scorpion IV. Just go and have a look and then tell me that a 3-wheeled (2 front, 1 rear) trike powered by a BMW bike engine doesn’t make a tiny bit of sense.