Sounds to me like your charging systems isn't working. If it were my bike I'd replace the stator.
I'm no expert but that's what it sounds like to me.
I don't believe the issue is your voltage regulator. I believe if your voltage regulator was bad the charging system would be putting out too much voltage and popping fuses.
I'm not an expert.
Those are just my thoughts.
So far you're doing a great job with your trouble shooting.
If I knew a test for the voltage regulator I'd post it for ya. I'm sure John(lunatic) or another Buell guru will get you straight.
Until then go to
www.buellmods.com and download a service manual. You should find trouble shooting procedures and the steps necessary to replace the stator in the service manual.
Good luck