I visit a Mario Kart Wii forum from time to time, not regularly, but...I'll get as many screenshots as possible.
Karts and Motorcycles.
Wario and Peach.
Wario, Bowser, + co.
One of the new characters, Boo.
Just search for some screenshots yourself, there are a few more. Check out Youtube as well. http://www.youtube.com/watch?v=1UKT4gZFWvk