Here's a couple to get the ball rolling. Iain Banks' admitted that while writing his first novel The Wasp Factory, he would insert a telephone conversation between the MC and his estranged, loony brother, whenever he started to dry up or worry about word-count. Even more dubious is Will Vlauntin's The Motel Life (yes, that book again). In it, the MC Will often tell his slightly backwards brother wild adventure stories that he supposedly makes up on the spot. When this happens, the author switches to italics and gives us the story in full - sometimes going on for four or five pages. So it can be done and get past the editors.