tluck- Success! This installation works 100% for the X220 Thinkpad including the battery manager. Compared to yesterday's repeated attempts which pretty much ate up most of my Saturday, today's new method had me up and running on the first build in under an hour! I am now wondering if my original installation attempts were somehow getting corrupted because when I started, the OS kept reporting that I was installing 10.9.3 via battery power which I knew I was not. This new installation method however supports battery management (and recognition) from the beginning of the installation.
A couple of brief installation notes for what it is worth:
1) I did not have to install the E1000 ethernet kext separately with either the original installation or this new one. Networking worked fine immediately following the kext installations.
2) There is something not working (at least for me) regarding the SSDT generation script. It goes out to download the iasl tool from the 'net but so far all attempts have failed. Not sure if the path is broken..? Fortunately, I had already manually created my own ssdt.aml file several days ago while attempting another OSX build. If this script works for others, please advise as I am learning and would like to know what I'm doing wrong.
If I come across anything else in question, I will post.. So far, very nice.
My hats off to tluck for a very stable OSX build on our beloved Thinkpads!