How exactly do you propose that the methods of transportation were "equipped" to your avatar?
Rollerblades are the only thing I can actually imagine in my head, as they would just look like shoes.
But being able to stand on a skateboard or surfboard, or sit on a bike, would be hellish for the administrators. Firstly, the methods of transportation would have to be unrealistically small to fit in the width of an avatar. Secondly, in the case of the bike or other sitting down vehicles, the admins would have to redraw the avatars in a sitting down pose and then change every single item to fit with this pose. sweatdrop
Personally I think it's a bad idea. Not just because of the extra work that the admins would have to put in, but also because I just can't visualise a Gaian avatar using any form of transportation sitting next to a post.