I'm not being a smart-ass, really. I want this place to exist, so I'm taking your word for it. I've begun a little investigation into where this place might be. :-)

They had new S4s a couple of months ago, and possibly RS6's there recently. There are often various Audi and Porsche test vehicles there.

Rumor has it that they like to take them up to the top of Mt. Evans, and also head out over Berthoud pass. FWIW, I saw a caravan of MB test cars there (Berthoud pass) this spring.

Steve