I remember when I was very young, I actually wanted to be a bigfoot hunter when I grew up.
Nothing sounded better than living in the wild outback of BC and discovering an unknown species,...but then reality set in & I realized there was no college for bigfoot hunting, and you couldn't feed the wife & kids traipsing around the woods all day.
While I can't say there is an unknown giant hominid species definitively, I think the prospect is very real.
I look at the primate fossil records and realize there's more than enough gaps in the plethora of genome trees for bigfoot to fit into. Particularly in the Neanderthal line. A species that was more successful(although ultimately doomed) than us by at least 200,000 years. From our limited understanding of them, they were clan based, lived in isolated areas, preferred cave dwelling, and were better adapted to harsher climes than us.
I don't think it's outside the realm of possibility for a proto-Neanderthal to be in a giant form, solitary or monogamous(leading to instinctual burial practices), hibernating, vegetarian, xenophobic(who wouldn't be if you knew humans existed & weren't one), and crossed some form of Alaskan land-bridge tens or hundreds of thousands of years ago to settle in the Rockies.
I've also traveled British Columbia quite extensively, being an avid camper & hiker, and as Schuyler suggests, there's vast stretches of impassable, dense, temperate rain forest here that I'm sure have never been touched by human foot or eye. Ideal conditions for such a species to persist and flourish away from all human contact if ever there was.
Who knows, but the recent Georgia bigfoot body hoax really left a bad taste in my mouth for the subject, and made me realize how much I/we really wanted it to believe it to be true, despite the remote chances, in hindsight, that it wasn't a hoax.