I want to ride with my son to his school, then tow his (BMX) bike back to the house before riding in to work.

I've thought about a cargo trailer and I was impressed with this setup for an Xtracycle:



However, it seems awfully silly to carry a bike when it has wheels of its own. Has anyone seen a rig for carrying the front of a bike, perhaps on the side of a rear rack?

It has nutted axles, so I'd rather not take off the front wheel.