OSx86 Project's CEpeep researched building a x86 machine that will run Mac OS X for Intel for under $200. The machine has the same Intel chipset on the motherboard and a processor with SSE3. Total includes CPU, MB, RAM, Case, HD, and DVD drive.

http://www.osx86project.org/index.php?option=com_c ontent&task=view&id=27&Itemid=2