Update: Apparently, this post has been attracting a little traffic from people who want to do something like this. For my x220t (the tablet version) hackintosh, I followed the guide posted here by user “peroxide”: http://forum.thinkpads.com/viewtopic.php?f=32&t=102098.
Note that the built-in wireless is not supported. I suggest a Mac-compatible USB dongle.
Everything seems to be working quite well except for wireless (intel cards are not supported) and battery indicator.