I was seaching for Hardy Boys pictures, and I found one called "Hardy Boys avalanche" or something like that.
It was like the cover art from the Casefiles before the TV covers, except I had never seen it before. It had an avalanche heading towards the Hardy Boys on it. Could it be unpublished Cliff-Hanger cover art? I can't seem to find the website though.
Here's a link to some unpublished Nancy Drew cover art, you might have to scoll down a bit.
http://www.synsine.com/artwork.html
Seems like another of one of the great Hardy Boys publishing mysteries. :o