I have just come across two different but equally neat motor-cycle-ish articles.
Nitin Khosha's Dacoit Street Cycle CG
In this great little article on CGSociety, Nitin gives us a breakdown of his creation process from design to final rendering. We get to see some initial sketches and some polished 3D work - another great example of just how cool motorcycles are as pieces of our mechanised culture. Nitin might not want these reproduced here, but here is a quick sample at lower qualty to get you over to his article.
[images of Nitin Khosha's Dacoit Cycle from his CGSociety page]
Yamaha Wearable Cycle Student Design
This radical design was one of many that students looking at more revolutionary design ideas relating to the motorcycle and environmental sustainability. Hannah Macmurray's article on GreenCardDesign shows us the wearable motorcycle design by Jake Loniak one of the students at the Art Center Pasadena in California. As you can see below it is spindley and fast - check the article for more on this and other designs. (and the CG work is quite decent as well)
[image of Jake Loniak's wearable motorcycle design from the greencarddesign site]