We've been extremely lucky and thrilled in the last few years. We were contacted by both Random House and Penhaligon Publishing company asking to use some of our keys on book covers.
The First was The Skeleton Key by Ralf Isau (the orignal key can be seen on *Drayok
And the second is the German edition of Incarceron by Catherine Fisher, which will be released March 2013 (We made a second silver key that will be on the second book when it comes out). We take NO credit in the book cover designs nor the edits made to the keys, we just made the models.
For Incarceron they actually also bought the keys
So for those finding these book covers, no, they didn't steal our keys or anything they bought the copyright to them. Just wanted to share ^.^ Not sure what category to put this in...