If the Piaggio MP3 leaning-scooter has taken your fancy, but you'd prefer something with a bit more grunt, Nick Schotter should be your first port of call. He's spent the past 20 years working on the 4MC (4-wheeled motorcycle concept), a bike capable of leaning 40-degrees to each side for super-speedy cornering.
Video demo of the trike after the cut
The prototype currently uses a Yamaha YP400 engine and a DIY frame, which add unnecessary length and weight. Still, it does all that without being as wide as a truck, too; in fact at 58cm the main body of the bike is narrower than many grown-up motorcycles.
Parked up, the hydraulic tilting system means the 4MC doesn't require a kick-stand, and at low speeds it can be locked upright so as to avoid the need to put your foot down to prevent falling over. Schotter is currently looking for someone to license his IP, and it could end up being Yamaha; the company produced a similarly tilting concept back in 2007.