"Obviously this is for an 8' bed only."
The bikes fit fine on the pin with my 6.5" bed. If I'm backing, and angle past 80 degrees or so, a bike tire bumps against my rear window. It's a harmless warning, and I consider that an advantage, compared to the metal crunching sound I have heard one time too many.
Part of the reason the geometry works is that much of the bike is above the level of the truck cab, and the bike length is shorter than the width of the trailer.
Another advantage: On the pin box, the bikes are always out of your way so you can leave them there. Also, when you're gone for the day, the bikes are on the more visible end of the trailer, and high in the air, discouraging petty mischief.