What If I Did This!? uses a photo I took of my first keris, which I also used for my letterhead logo. (You can see the logo on the grip of the Colt .25 ACP pistol on the cover of Bristlecone, below, scrimshawed into the faux ivory by Yours Truly.)
No Man But A Blockhead uses a public domain clip-art concrete block. Both will be up on Amazon.com in a couple days, and I've changed them in the book listing here.
And the beat goes on ...