Now you're thinking, fuses are expensive, a test light is not. So many wire crammed so tightly inthe area you're dealing with won't make it easy but now that it's leaning towards the dead short side it shouldn't be hard to pinpoint.Put a light across the blown fuse - it stays lit while I rattle the wiring harness until I hit it near the headlight (flickers). Maybe in the headlight/connection box... It was too hot to continue - hope I can get to it tonight.
Maybe you can use an Infrared gun to look for temperature irregularities/high temp = short/bad connection? just an idea if you can borrow one. You can certainly check your fuse blocks to see if on side is hotter than the other?