Is there a way to evaluate OS X without purchasing Macintosh hardware? I'd like to play with OS X to see what makes it tick under the covers for the purpose of IT support - at CWRU here we have a lot of Mac-using professors. However, I can't justify spending twice as much on hardware as I would purchasing from any other vendor. Therefore, I'd like to avoid getting Apple hardware. I know you do get something for that money (nobody else does anything like Apple's aluminum unibody), but I don't need that for what I'm doing.

(Even the cheapest MacBook Pro is $1,199.00 -- compare to Lenovo, which itself is one of the most expensive PC makers, $809.00 for the same specs. [Okay, the Lenovo has a bit smaller hard disk, but it has a faster CPU and discrete graphics, so it's kind of a wash.])

Is there any (supported) way to do that or am I forced to purchase Mac hardware?
You can't run Mac OS X on non-Apple hardware. It's not allowed by the EULA for OS X and it is technologically enforced by having key parts of the OS in the copyrighted hardware ROM installed in the Apple hardware.  Furthermore, all versions of OS X prior to Leopard and non-server versions of Leopard and Snow Leopard had architectural issues that prevented virtualization even if you wanted to hack something like VirtualBox or VMware to virtualize them in violation of the EULA and copyrights. 

Incidentally, while you can virtualize OS X Leopard and Snow Leopard Server as well as both versions of OS X Lion, the license still limits this to Apple Hardware. 

VirtualBox supports virtualizing OS X Snow Leopard Server. You can find instructions for doing this here.  VMware Fusion supports virtualizing OS X Leopard and Snow Leopard Server as well as OS X Lion client and server versions.