Here's a name for a coaching candidate that no one has brought up: Ettore Messina.
I assume that most of you are saying to yourselves "who?" at this point so let me introduce you to Messina. He is a 47 year old Itallian born coach whom has won 4 Euroleague Championships (including 2008). He coached and developed Manu Ginobli before he came to the NBA. He is known as a defensive genius.
Maurizio Gheradini, the assistant GM of the Raptors, has been on the record as saying
"He [Messina] can rank with the very best. Messina breaks things down in a different way. He understands how to teach the game and how to put the right emphasis on the teaching points. The guys under him, they're always awake when he's talking. The guys cannot relax one second. They have to be awake because he is so detailed, demanding, critical, you need to be awake to do things the way he tells you to do them.''
I'm not saying that this guy should be the top candidate on the Bulls' list, I favor Thibodeau, but if the Bulls can't get Thibodeau for whatever reason I think this guy is someone they should give a serious look at. This guy is the best foreign born coach right now. He's a proven winner, and he's a great x's an o's guy. He also speaks perfect English so the language thing won't be a barrier.