The cabinets to the left and right of the window are both 12" deep.

Thanks. Deeper than I thought. I've been thinking about adding very shallow cabinets to one wall in our kitchen -- 6 inches deep. Do you have any opinion on using cabinets that shallow? I want to go that shallow on that wall so the cabinets don't come out past a window on an adjacent wall...

The depth of a cabinet depends on what you want to use it for. 6" is deep enough for you to fit some glasses or perhaps for plates standing upright to showcase, and if that is what you are looking for, then it should be fine. Just keep in mind what you want to store to help dictate the depth.