Suddenly, this whole question seems to make sense to me. Obviously, I'm tragically mistaken about something... but bear with me.
The implications of adding a second, or bigger motor rather than a transmission started falling into place when I starting thinking about adding a two-motor configuration to the R5e. Here's the basic jist of it.
When you add a second motor, in parallel, then you're doubling the torque (and load) at any given RPM. You're also doubling the current handling capacity- a 300amp system becomes a 600amp system.
It's all about the overall system. The ideal system has current delivery and motor load that's balanced. If you have high current delivery but your motor is not big enough, you need to add motor (either by adding a motor, or by substituting a bigger motor). If your motor is not running close to it's capacity, you need to add current delivery, or, if you have maxed out your current delivery you can add load to the motor- through gearing- either just adding taller gearing if the motor has the torque, or adding a transmission to spread the torque out on the curve. Or the motor is simply too big for your system.
Even as I type this (as per Jack Rickard "typing yourself smart") the transmission starts sounding like a bandaid for a system that's poorly balanced...
Anyway, more here: http://evmc2.wordpress.com/2012/01/0...s-dual-motors/