Note that each stepper driver would require several Arduino pins so the total pin count will be quite high.
In theory you are right.
However, I'd take a look at the approach LadyAda had with her Motor Controller Shield: the shield has 2 x L293N, which would
require 4 pins each from the Arduino. She, however, used a single 74HC595 to interface with the Arduino, and the 595 is in the shield.
Using the same approach, one can have up to 16 steppers, each one with its own driver, and each pair of dirvers controlled by one 74HC595. Since the 595 can cascade, they'll only take 3 pins in the Arduino.
So, using a $0.50 IC, which is the 595, you can "multiply" the number of output pins in the Arduino, but taking ip only 3 pins in the Arduino.