[asid61]

You prolly don't need it, but it's easy to add another.
EDIT: I was a little rushed, let me go in a little more depth.
If you are doing a coaxial swerve drive, then it's easy to add another cim. If you are using chains to the pivot shaft, then wrap the chain around both cims. Same for belts. Just make sure you have enough wrap around the pulley/sprocket that the teeth don't skip.
If your cims are turning with your module, it's still not too complex. You just end up with a much larger module, and as a result I don't recommend going 2 cims if you do that.
Doing a cim-in-wheel swerve will be nigh on impossible to implement well with 2 cims.
Another choice could be using 2 minicims per module. That gives you more power than 1 cim/module, but not so much as to easily cause brownouts.