Great pic from Alguersuari's blog, that really made me think about the issue. I have seen several of them, mostly in bikers' event and for sale, not on the road... but they look hell of a practical device! On long trips they give you a quite good way to carry your stuff. Furthermore, I think there are some of them in which you can sleep in. I know they might feel a bit of a coffin, but who cares anyway! I wish some more effort was put into this by the motorcycle companies, and they issued their own trailers.