Thanks for the fun hunt, I had a great time. Galoot is not a word one hears much in NZ, but it seems that there are several theories about its origin, none claiming to be definitive. Here are a few links that may add to the murkiness

http://www.takeourword.com/Issue032.html
http://www.randomhouse.com/wotd/?date=20000217
http://www.word-detective.com/back-x.html#galoot