Maybe a used Thinkpad T60p. Some of the 15" models had IPS (a.k.a. Flexview) screens. However they're kinda old (2006-2007, which means Core Duo usually, upgradeable up to socket M C2D). You can find them for $500-$600 used.
You are really asking for a lot more than you think OP. High viewing angles and cheap dont go hand in hand. Best advice is to do what Pylon said and look at getting a T60p...however, even then those arent guaranteed IPS panels...those were an extra option that could be added.
Other than that try asking around on NotebookReview forums or so...like I said, what you are asking for is hard to come by.
Have you thought of getting an iPad? Obviously way behind a actual laptop, but Ive heard they have great screens...albeit 4:3...
I wouldn't expect big bargains for a good screen. The first that comes to mind is the 13-inch MacBook Pro, since it has a very good display, but I wouldn't be surprised if there's a cheaper alternative... if not by much.