allegro microstepping ic

As has been said here before allegro makes some nice stepping control
circuits. What I am wondering is this - They have a few
microstepping controllers like this one.
http://www.allegromicro.com/sf/3967/
would it be possible or has anyone come across a working circuit to
put an external h-bridge of mosfets to handle more current? And could
the current sensing still be used so the microstepping and current
control still works.

These are nice little ic but like the one above they handle such low
current.

thanks
sam