I came home from work the other day to my truck in the driveway with the backup lights on.I unplugged my trailer - no short there, they stayed on. I played with my override switch and my shifter, they didn't turn off.I pull the backup light fuse and they stayed on.It seems that the hot side must be shorted to voltage somewhere after the switch on the trans. Anyone have any ideas on common bad splices or pinch points? I've got no guesses on likely areas myself, thought I'd throw it out there and see if this was any sort of "common problem" that I'd just never stumbled across.

Ok... The stock backup light are after the key so if you turn off the key the lights should go out. So that means there is a short from +12V to the lights feeding the circuit constantly. I would check over your wiring and any modifications you might of done to the reverse lighting.