Well Put SlowPro48... most people won't think very much about tongue weight and whatnot. The physics work as you said but many people don't want to put too much weight on the tongue and load down their trucks rearend... but that puts you in a bad position... especially given the short wheel base and other things you mentioned.
Now back to that tank... have any pictures of it yet? I wanna see what your gonna be playing with. Also, that Rip-Saw video... I found their main site and must say... that thing is down right wicked! I wonder what it would cost to build something like that... or have built... just crazy!
Later!
Coach