you may have missed it in the first post but I actually have tried making my own a few times. it's decent but the mae ploy is better than anything I've made. I'm not sure if it's b/c I can't get galangal (used ginger instead) or some other ingredient was missing or what. I do not have access to fresh kaffir lime leaves to the best of my knowledge. the north east is not exactly citrus country
as far as I can tell pretty much every thai place I've been to uses mae ploy or something that tastes extremely similar. I hear it's commonly used in Thailand as well.
The Super 88 chain of Asian grocery stores around Boston carries galangal and kaffir leaves, if you;re ever down this way.