For a while United had a YUP fare JFK-LAS, which booked into A on all non-TED flights and Y on TED flights. It also allowed routing through SFO/LAX, thus allowing first on 3-class planes. Thus, one could do JFK-LAX (First) LAX-LAS (Ted) and back for only $700. However, I believe United recently changed the rules to make it a QUP fare that couldn't be used on 3-class flights.