Sorry to say I don't have an idea for a book - just chiming in to say THAT'S AN AWESOME PHOTO!! WOW that has a lot of character! Thanks for the link!

I'd thought about doing as book on tattoos, but that wouldn't work for B&W.

As far as the Vets, you could have a portrait on one page, and a story from them on the facing page. Just a thought.
Given you're next door to Tennessee (okay, you COULD be 6 hours away, but just thinking out loud... and besides, you MUST have local music around somewhere), you could do a book about local singers and clubs - think older musicians in Blues and Jazz - their faces (like the link) have more character and history to them. There's a fantastic pic Mark Seliger did of John Lee Hooker's hand - just the top of his hand in B&W with all the texture that could fit on a negative - it's amazing!

What do you LOVE? Shoot that?
Good luck and have fun-
-Lew ;-)