Not an upgrade, but pretty close. Last summer I was on vactation, flying Icelandair from Boston to Frankfurt on a dirt-cheap (for August) ticket. I was one of the last 2-3 people to check-in, and did not get an aisle for the connection from Reykjavik to Frankfurt. Not looking forward to sitting in a non-aisle seat on a 757, I asked in Reykjavik if there were any other seats available. I was assigned to row 4. On board the plane, I discovered that rows 3-4 were business class seats by confguration, but for that flight located in the coach section (I guess they had undersold business class, and wothout the extensive FFB partnerships didn't have demand for upgrades). While I had coach service, I got the best part of business class--the seat--for almost certainly one of the lowest fares on the flight and with no elite status. The person sitting next to me was in the same situation. Got the same treatment on the return as well. Lesson: it never hurts to ask!