I haven't done more than briefly glance at this interesting-looking website, but this man would probably be a good person to ask. There's quite a lot of historical info about sources if you click on some of the links - worth looking at in greater detail than I've had time to do at the moment (sorry, the Mudcat blickifier is still taking forever, thanks for the other clickies, Maeve). Surely Lewis Castle must be in some of the other collections as well as Walsh if it was a popular dance tune.

http://www.scotmus.com/music/index.html

http://www.scotmus.com/index.html