Well, it seems (and this can be looked up easily on the internet) that there are lots of stories and legends about a race of giants in North America. These stories are very interesting, because they're coming out of the 19th and early 20th century, from settlers, rather than from pre-Columbian times.
Apparently, there were gigantic humanoids (between 7 and 12 feet or more tall) in Tennessee, Ohio, Kansas, Wisconsin, California, Indiana, Minnesota, and New York. They share other traits than bigness, too. They almost universally had a double row of teeth (this trait comes up again and again) and usually red hair-although some legends tell that the red haired giants displaced other black haired giants. Lots of skeletons were apparently found-especially skulls, and with artifacts, like stone axes.
So, I was thinking, why not a giant Native American influenced nation? Kind of shine a light on these rather interesting stories. I can provide more details about this, if you or anyone else is interested.
Here's one link:
http://www.stevequayle.com/Giants/N.Am/N.Am.html
I typed "Giants in North America" in Google to find it.
It might be that the scientific community is doing some covering up, because I've read quite a depressing few accounts about these discovered bones "disappearing" into various institutions.
Maybe it's a conspiracy, maybe the whole thing is just made up, but usually there's an element of truth in such a broadly-told lie.