I didn't know Tonto was Canadian either until I read that article. What got me to Google kemosabe was your statement that no one really knew where it came from or what it meant. And I came across that article...

The dictionary states it means Great Friend in several Native American languages. But then, I also read a few times, that when Indians were asked what it meant, none of them knew.

I, too, have wondered...

~ Dazzle