Speaking for myself and my wife, neither of us see the point of spending the money and taking the time to build / customize a trailer that is taller than a teardrop but not tall enough to stand upright inside. We have spent countless years crawling in and out of small tents, pickup beds with toppers, and the like. We have also had small factory made "eggs" than we had to hunch over inside, as well as two we could stand erect inside. If you've looked at our current project you know what we are happiest with. YMMV.
If the height costs us a mpg penalty it won't be all that much more compared to a trailer with 6 foot interior height, which is more or less standard in its class.
I do have to measure the height and write it on a card that will be pasted within view of the drivers position in the TV.

Don't want to make a youtube appearance in conjunction with a low bridge.