Not sure if this is what you were looking for, but I found this over at XDA yesterday. It was exacly what I was looking for...
Just unload TouchFLO, reset, and replace the file in the "\windows" folder with this one. This removes all the countries and gives you just the US cities. Worked perfect for me.
http://forum.xda-developers.com/showpost.php?p=3519352&postcount=862