Weigth and thrust are just arbitrary [although related] numbers. It's all down to the airframe. Primarily the aspect ratio of the wing.
Although there is some interesting work with the
Prantl-D wing. It uses washout on the wingtips to deflate wingtip vortexes.
http://www.nasa.gov/centers/armstrong/news/FactSheets/FS-106-AFRC.html
Something something span-wise loads something.