Hey there Mike, I hope the fuse turns out to be the solution.
In case it isn't, it might be a flex-to-break problem in the wire loom located at the bending point where the wire loom traverses between the triple clamp and steering head. (If you can even call them that on a telelever.
I know, why is the dipped beam wiring going to the throttle perch? If I remember right the power supply lead for the headlights first travels to the right side throttle perch.
Inside the perch the power supply lead splits into two leads, one each for the main and dipped beam. The low beam wiring runs up to the handlebar perch because Europe bikes have a 'headlight off' switch for use in well-lit urban areas. (That's what the low-wattage position lamp in the main beam reflector is for.) The US bikes don't have the headlight off switch, but the wiring is there, and there's a jumper plug in place of the switch to route to power to the two headlamps.
Anyway, that steering head flex point is a common cause of shorts and open circuits in the wire loom. I don't know what additional wiring you installed for the HID lamps, but a innocently-placed zip tie could have been the last straw for that steering head bending point.
p.s.: Ordinarily I'm all for that the solution is most often the simplest one, ala Occam's razor. But it looks like you tried all of the simple ones so far.