Correa, I think a good place to start is the wikipedia entry
here. (More of my wiki abuse, I know.)
From the article:Check the Kennewick Man reference in the American continent connection section.
Very interesting stuff.
OK, I see my memories were a bit selective...
From Wiki on the Ainu:
Some have speculated that the Ainu may be descendants of a prehistoric race that also produced indigenous Australian peoples. In Steve Olson's Book, Mapping Human History, page 133, he describes the discovery of fossils dating back 10,000 years, representing the remains of the Jomonese, a group whose facial features more closely resemble those of the indigenous peoples of New Guinea and Australia.
Is roughly what I remembered.
But consider the Kennewick man and remember Luzia, a 11.5Ky-old female from Brazil (
http://www.andaman.org/BOOK/chapter54/text54.htm#luzia) that is not related to current South American indians, but Australoid or southeast Asian. This indicates there were pre-Clovis human populations at North America.
Now, picture yourself as a member of a Clovis tribe telling your grandsons about these other people. Maybe you waged war against them... How would you decribe them? Would you resist the temptation of adding some "extra details" to make them more fearsome and you more brave? Maybe telling they were tall and ferocious?
Then your grandsons would tell their grandsons tales about that ferocious people, and eventually add their own details... Perhaps saying they lived among the woods like wild animals... Tall wild men.
Some generations later and they become hairy, to add emphasis on their "wild side".
Eventually the "tall hairy wildman" can be used as a charachter in many legends and tales, assuming different roles and variants start to appear.
Heck, it does not take any pre-clovis population(s). All it takes are "the others", the "people who are different from us".
I have no evidence this happened. I don't claim it happened. Of course it may have happened (or not). I bring this just to show there is no need for an actual unknown bipedal ape as a template to sasquatch myths.
Homo sapiens can well be the template.