axle mounted esc's aren't totally unheard of in Supers.
here's one example of a nice one. the esc's are tucked away in an area that is fairly well protected by the wheels, and there is no speed at all. if the truck flips or falls, there won't be any impact on the esc. i just have to worry about no servo saver. i already had to replace the gears in the front 645mg due to running into something with one front tire too fast....
stripped out instantly.
once i get a nice sunny day, i'll take it out to a nice crawling spot and get pics and video.
edit: i just read the review of the stealth in the latest RCCA (p. 124/125) and they added dual axle mounted MM's too.