The bent boom is a marked departure from the more traditional straight boom found on most other tadpole trikes. This configuration would be difficult to achieve using another material but the real reason is for looks. While some like it others noe so much. Beauty is in the eye of the beholder and in this case, if you took the side view and took the bend out, the lines don't flow as well. At the end of the day, it has nothing to do with the performance of the machine which is the most important factor. As far as a pratical "man" powered machine, that is a typo and should have stated human instead. There is a much longer story about the INNESENTI and how it came to be but it was a woman who spurred the development effort and rides one today. I think someone mentioned it was too narrow in both track and seat width. The track is set so that it will just roll through a 32" door but it dosen't cause excessive tipping in corners. The seat can be customized as necesary to fit the rider and riding style. We are working on a new seat pad as we speak to provide an even better fit.