Diptychs is the name of one of my favorite image blogs. I go here all the time when I'm looking for inspiration for The Flooding House. I have even found some great image inspirations on Diptychs for Paramour is Unrelated. I love these people!
This is a link to my alltime favorite picture they have posted: Sort
I think the other thing about Diptychs that fascinates me is that these images are not just made at the hands of one person. It's two different photographers whose images are side by side. What collaboration!