When I made a bag for my daughter I just made sure that it had plenty of padding in it and an extra layer of foam in the bottom for those times when she plunked it down hard. I used the pattern called "the professional bag". I did put a zipper in hers but you can easily add a flap. I've also seen a sized up Bow Tucks used as a laptop bag and all those pockets are good for the other cargo you carry with.
http://pursepatterns.com/index.php?m...roducts_id=124