Cool Idea!
Allegro makes good parts, as the last two posts have pointed out.
Another source you might want to consider is GMW Associates. I haven't tried them yet, but they look interesting:
http://www.gmw.com/magnetic_sensors/...Acc.html#AN119
A "better" method of current limiting might be to just inform the driver that she is about to pop a breaker. Remember to include an over-ride if you do close the loop in software. A driver might need that little extra oomph, even if it means popping breakers a few seconds later.