Thats a freaking cool system. When I was in Queenstown my tour giuide used that kind of system for our bikes with one small change. The sides were hinged so the the tyres of the bikes were essentially locked in, see photo for what I mean.Im not a fan of crank holders either.......
*Cranks are either too tight and jam or too loose and flop around in the holder.
*They scratch the crank arms
*They are a hazard to rotors / pedals when loading
*They are a trip hazard to the person loading
I designed our trailer with my dislike of crank holders in mind.
*Quick and easy to load
*No damage to cranks
*Fits all size cranks , haven't found one that doesn't work with our trailer yet.
.....and yet my cranks are scratched to the f... from using club trailers at races. Oh well.....
We could fit 9 bikes on it with extra racks , but seeing as the car only takes 5 people , no point.
EDIT: Unitecs trailer looks cool , nice idea.