I found Ketter's work on one of my favorite blogs, Le Divan Fumoir Bohémien - the one that makes me sad my French is so awful. (Bonjour Florizelle!) He deals with construction sites, the negative space that's left when structures have been removed - I love it all. His most recent show was Gulf Coast Slabs, but I've found older work as well. Although he has lived in Sweden for many years, I was excited to see he is a fellow Mainer!
I won't post images here to confuse matters, but there is a flickr pool called The Unconscious Art of Demolition, with images of ghost shapes of old structures from which I've culled a lot of favorites.