Found the culprit! After removing the side panels and some of the front ones with no success, I stopped by the shop where I bought the bike, and the service manager took a look with me. At first, he also thought it was coming from the instrument panel, but on closer examination, it turned out to be the Denali lights. I had tested the light bar I was using, but it did not occur to me that the lights were also vibrating just enough to make the noise. It took all of two minutes to tighten them up, and now I am once again undisturbed!! Thanks for all the suggestions!