Controlling multiple stepper motors

I'm planning to control about 10 stepper motor peristaltic pumps from an Arduino. Do anybody have clue on where I can find a motor controller that is controlled over i2c or spi or is there any better way to control such an large array of motors?

What do I need to know about the motor to accurately select a suitable motor controller?

Sounds like you need step & direction interface, two wires plus ground per motor.

For low-speed operation you could conceivably share the direction line as it is only sensed during the step low->high transition.