Benefits for Clippers: Get a young healthy point guard, and two expiring contracts. Khryapa could be worth a look as well. Duhon could fit a rebuilding effort if Mags and Brand end up leaving. He'd also have interest as a free-agent and could be a guy who could get you a sign and trade to a contender like the Spurs.
For the Bulls: Cassell becomes their best post player (yes it's that sad), is an imediate upgrade over Duhon, gives them a true leader, second clutch player to Gordon, and replaces Boylan next year

Cassell may be slow and is probably a poor defender at this point, but so what? He'd help our Gordon-less lineup offensively, and would be a vocal leader. I really like Duhon, but having such huge shooting slumps two seasons in a row is unacceptable.