Have you seen this website called 21Bikes.com yet?
There are pictures of bicycles (and unicycles) and their owners submitted by people from all over the world.
It’s cool because you can upload a photo of you and your bicycle and if it’s good they will post it to the site within one of the 21 bike-specific categories. Then, once the picture goes live, it gets voted on and shared by people from all around the world.
There’s a cool unicycle photo that was just posted today by Mike Penton: http://21bikes.com/2009/10/22/unicycle-swinley-forest/ but it looks like they need some more uni pics.