Yeah, I was wondering the same thing about mounting that top bracket in place of the seat post clamp. This way it would be a dual purpose attachment for the seat and then the trailer. Then mount the lower bracket a few CM lower than what you have now. I don't have experience with hitches though, so I don't know if mounting it lower would be better or not. Still looks nice though, good metal work .

Slightly off topic, but I'm not exactly sure why the seat post clamp is better than a clamp near the chain stay (as with a kiddo trailer). I just got a trail-a-bike set up for my son and figured that the seat post mounted attachment would suck! Man was I wrong! I love the attachment in that area as it make the bike so much more stable vs. the chain stay mount near the rear hub.