Very simply put.... take an old tubular lock key, shave it down to where the sides of the key is thin enough that you can put picks in there to push the pins. Also... add a bar across the top as handles.
similar to this.... http://www.youtube.com/watch?v=kRyM7NrmHSE
or this.... http://www.youtube.com/watch?v=GsTSHeXkN5Q