It seemed to be coming from the front end, and I thought it was suspension related because it was definitely related to vibration/bumps. It was a high pitched high frequency squeak that was particularly annoying at low speeds.
Anyway, long story short, it was the hood latch. I put a couple of wraps of electrical tape over the latch and the squeak is gone! I know it is probably only a temporary fix, but at least I know what it is.
I'm going to buy some new hood bumpers to see if they can fix it permanently.
