Reviving this thread for a moment to report on how it all worked out: he's been commuting with a Cannondale CyPod pannier, which he really liked, and in fact he was thinking of getting a second one. He can fit most of his stuff in there, but it's easy to carry as a messenger bag around campus, and it looks good enough for client meetings. Once in a while he has to carry his laptop separately in its own messenger bag, but usually he can fit everything he needs in the Cypod pannier.

Except ... this morning I got a call about fifteen minutes after he left for class, asking me to come pick him up, because the plastic hook that holds the pannier on to the rack just broke in half. So the $120 pannier is useless after only about a month and a half, and this afternoon he is going shopping for an old-school Wald wire basket.

Fortunately he bought it from REI so he can get his money back. Not a good design, there.