Heh, I'm scared to death of heights, too...but not chairlifts or rollercoasters, interestingly enough. That glass lookout thingie over the Grand Canyon sounds like a sort of Hell to me, though.
I agree with you. I've been to the one at the Grand Canyon, but there is one at the House on the Rock in (don't remember if it's Minnesota or Wisconsin). I couldn't walk very far out into that room. I'd think the one at the Grand Canyon would be worse.