I can understand why Kevin wants/needs more power. Check this beast out:
http://www.dragonebikes.com/x20-clone.html.
As per our Canadian code, it's rated 500W at 48V and has a top speed of 32 kph - off a cliff maybe. I wonder if the 103 Kg net weight includes the 48V 20AH lead acid battery.
I did a quick search on "synchronizing hub motors" and found very little, but I didn't pursue it far. Two MP III's on one throttle is likely the easiest setup to get up and running. Two MP II's on one controller (Lyen 24 FET at approx. 80A output) might work too. Just thinking out loud here.
However you try to drive the two hub motors, and I'm assuming you want to drive the two rear wheels here, you're going to run up against the problem of the difference in speeds due to different radii in a corner. This is why mechanical differentials were invented.
In the case of two MP III's on a single throttle, I would expect the inner controller to try and compensate for the slower speed by increasing it's power, while the outer one reduces power. These are powerful motors and I think the effect on your three-wheeler would not be insignificant. The (possible) upside is that this same effect would result in a system with self-correcting straight line tendencies. Great for the prairies maybe.
Two MP II's on a single controller? You wouldn't be wanting PAS to start up that baby, so one set of hall effect sensors would have to go to the controller, and... nah! Back to the same radii problem. Of course, if you put one motor on the front and one on the rear, the radii problem would be lessened.
Obviously, smarter people than I have already pondered on this, and guess what? I think that's why mechanical differentials are still popular:
http://www.samagaga.com/Default.aspx.
