Came across this beautiful chassis design. It is not human powered but would be easy build something similar to this for a velomobile chassis. I love the simplicity of it and of course the sustainability of building in such a way. This has inspired me to go down this route for the design of Veloci-Velo chassis. I had almost finished a more conventional aluminium frame type chassis but when I saw this I changed my mind. Stay tuned as I make up some drawings and then get to work!
More info about this design here ... https://tadpolerider2.wordpress.com/2014/09/04/electric-recumbent-trike-race-wood/