I am building a trailer to tow behind my automobile. It will be a short (32" tall) enclosed cargo trailer (for luggage). On the roof of the trailer will be a homemade bike rack to transport six (6) roadbikes (from OK to FL). The footprint of the cargo box (50" wide, 60" long) can be smaller than the footprint of the bike rack. Think of the many cars and SUVs you've seen with roof rack crossbars that are much wider than the vehicle they're attached to.






Until I started studying these Tour de France team chase cars, I had thought that the most space-efficient layout for transporting six bikes would be something like this:



but now I'm not sure.

I plan to build my bike rack using fork clamp mounts like this:



which will be bolted (or tack-welded) to my cross-bars. I'll use some extruded U-channel for the rear wheels. I can build this myself for hundreds less than buying Yakima sproket rockets (or the like). Unlike a store-bought system (Yakima, Thule, etc.) I am not limited to having only two crossbard or a spacing pattern imposed by the car's geometry. I can do pretty much whatever I want. But, at the end of the day, I'd like it to be as compact as reasonably possible.

Does anyone have any suggestions for the most space-efficient layout for transporting six bikes?