Often, upstairs business-class lavatories (on 747s) have windows. I find it very nice, especially when there is sunlight coming in (and night you usually can't see anything at 35k feet anyway). I've flown recently in upstairs J on QF, CX, and JL. I know at least some of these have windows in at least some of the lavs, but I didn't make a note of which ones, although I think it is the forward ones.