100:1 Micro HP driver recommendation needed

I am working on a small 4WD rover and I am looking to drive 4 x 100:1 Micro HP motors. I was planning on running the two pairs in parallel from the Baby Orangutan 328. However, I am beginning to think that it may not be able to support the current. Any thoughts?

You are talking about a setup with over 3 A of stall current per channel - that is right at or slightly above the limit for the peak output current on the Baby Orangutan’s motor driver, which means that unless you are extremely careful to never get anywhere close to stalling, you will probably destroy the chip. You probably are not going to be happy with this setup, so I recommend getting a more appropriate driver, like the MC33887. It might be easier for you to use something with a serial interface, like the Qik 2s12v10, which should handle a couple of HP motors with no problems.