ArtMetal

Michael,
On the foredom not sure if would have enough power to move the metal the way you want to do for repousse. Never tried a foredom but I have tried the little electric chiesel hammers and they just buzz.
I have used an air hammer for doing some repousse and chasing. Just rough work but it works if you have the proper air hammer. You need one that has a feathering type trigger so you can vary the hammer hits.
There a few metal artist that use the air hammer for all of their work.

warren
http://www.metalrecipes.com