I have hear of people replacing those motors with Ford Taurus electric radiator fan motors. But, you will have to reverse the direction of one of them.
looks like your out of luck. I couldn't find one doing a Google search - finding a pair, even better luck! Suggest maybe you modify the bike to run a different electric motor kit. How about an electric wheel motor? Here's a place that sells surplus electric bike parts - no Ev Warrior though: http://www.evdeals.com
Here's an interesting article that mentions Ford radiator electric fans, as Esteban suggested:
Good link above. I lifted this from the link . It shows how to change the rotation of the motor since they both cannot turn in the same direction. Ford Taurus motors are pretty cheap, even new, but I might would get a junk yard one to practice changing the rotation on, since it looks like a lot of work.
Any interest in 2 EV Warriors with 1 charger. Original owner says they just need new batteries, but haven't confirmed this yet. Both appear to be complete and in good condition.