Hahahhaha, double post but a bit of an update-
I've got some basic measurements out.
Chassis should be about 9 inches long folded, 1 1/4 inches side-to-side, 5 inches tall.
I'll start doing a better mockup when I get some plasticcard, and then design the pieces and internal mechanisms. After that, it's time to get something three-dimensional done- and then a prototype?