[motto]

I would imagine that so long as they were coordinated it would have some effect but wouldn't it look funny! Sometimes merely having a couple of ton on board or removing outside duals will make a truck perform better.
There was a fellow in Queensland who had a replica VW Kubelwagen. It had a rear bumper that was ideal for standing on. With one or two blokes traveling on the bumper to bounce at the appropriate time that vehicle would go anywhere a Jeep would go.
That was the first vehicle I'd seen 'bounced' for traction and I remember being surprised how effective it was. Probably more effective because of the bouncers (bouncees?) being right at the rear.

David