Off-road trailers don't have to be very expensive. I know you're just sharing a cool link, but if you were actually interested in a trailer for such things the Expedition Portal forum is a great place to learn more.
A trailer that I think is pretty awesome, but will never work for my large family is the Cricket:
Lots of well thought out amenities in a small package. I just don't know how well it would fare on the road to Baja.