So far I've found two recent webcomics that paid tribute to Mario Kart Wii. If I find anymore, I'll update this thread with more links.

On Wednesday, GUComics took an artistic angle at 1up.com's challenge to create a custom Wii Wheel. The result? Well, you'll have to click over to the comic to find out!
Link: gucomics.com

Penny-Arcade applies one of Mario Kart's deadliest weapons and applies it to a real-life situation.
Link: penny-arcade.com