Well thanks for all the good nd nice comments, guys.
I can provide some pictures of the current state of the monocoque development (it will be originally looking from the outside but heavily numerically optimized):
I use similar proceedings as in my masterthesis. Purpose of all this is to get it as light as possible but also stiff to attain the highest driving-quality possible with metal design. I started with making up a design space, which can be occupied by structure. This design space was then meshed in order to obtain mechanical results from it and then I put it thrugh a topology optimization. This does kind of the same as growing does in bones. And the results showed that a thinwalled substructure (as in the Ferrari 330P3/4) made up of tubing fulfills the strength- and torsional stiffness constraints most optimal. These results are quite "rough" (as you can see in the pictures), but that doesn't matter as you only need it to place your redesigned structure. This first optimization does not account for eigenfrequencies (vibration) and dynamics, so after the discrete redesign (as you cans see in the pictures) I am at the moment pre-optimizing wall thicknesses of the tube-substructure. This is then fit in certain areas with sheet metal in order to get the original look, high eigenfrequencies and - most importantly - dry clothes when you drive in rain. So I hope in the end I will have a design for a monocoque weighing approx. 120-130 lbs AND having a torsional stiffness of at least 10000 kNm/deg. Sorry for the metric number, I was to lazy to convert it (must be something around 14000 ft lb/deg).
I hope the pictures explain some of it.
This work is really exhausting as you keep typing numbers and design surfaces, but I hope in two to three months time I can do the laser cutting, welding and fitting of all that stuff in real. Looking forward to it...
Thanks for your interest.