So does dipmicro ave H-bridges that would work with a stepper motor and an arduino?
Yes. For some stepper motors and some definition of "work with"...
I don't think that it was the missing H that Mike was complaining about...
In particular, DipMicro seems to have both the L293D and the L298, which are pretty common H-bridge chips in the hobby world, and used in several motor driver boards. But I don't see any actual "motor driver shield" products, which means that these will require some effort to connect to an Arduino.