...its seemingly totally random. Maybe I should splice a fuse into each wire everywhere and see what pops? I mean, being so intermittent like that leaves...not much else...but 
That would be so invasive though. You'd be more likely to introduce issues with all of the wiring disturbances.
So an update:
I broke down and took it to a stealership. They sat on it for 2 agonizing weeks, then started riding it to 'replicate' the problem. Told them it was futile, why the F$@K arent you runnning down the schematic and testing things...long story short, they did nothing but charge me 50 bucks to tell me its fine, and they coulnt find the problem...
Unfortunately, as in all professions, some mechanics are better than others. Sounds like you encountered the second type.
A lot of mechanics don't like to work on older bikes, and they will almost all complain about having to troubleshoot electrical problems.
For instance, I just picked up a "day job" at a local stealership, as the Accessories manager. You'd think that someone would have been able to tell a guy how to remove the passenger seat from his mid-80's shadow before he got to me,.. especially since he had already asked in service. In the end, I showed him how to remove it. The young farts in service couldn't figure it out.
Do keep in mind too, that not everyone in service is a journeyman mechanic....
We'll take a look through the wiring diagram this evening, or tomorrow night to see if we can try to point you in the right direction, but right now, look at the connections that you share with the fan motor, sidestand relay, ignition switch and ignition relay. It looks like all of these will share that 10A fuse.
Where
are you located btw?
