Some very cool stuff on this thread! BTW, a quick Google search found a three-view drawing of the Tank:
Purely from an aesthetic point of view, I think a slightly shorter nose with a steeper rise would be good. I also think a slight curved dip next to the cockpit would "sell" the Tank-ness better without
too much negative effects on the aero. Even though I think the angle of the rear of the original looks better than what I am seeing of your design so far, I am betting that yours is more aero and definitely more driveway-friendly....
-soD