I sit here at my local Mazda dealership waiting for them to pop the transmission apart from the engine. I hopped in the car on Saturday to head to a soccer game and as soon as the I pushed in the clutch to put the car in reverse, I heard an odd whirring noise. My friend with the blue MX-5 had the same noise a few months ago, just after he bought the car, so I have a pretty strong idea that my throwout bearing failed. The noise only happens when the clutch is depressed, and goes away after the engine and transmission have warmed up. That will make this dealership trying to reproduce the issue awfully interesting, to say the least.
The bad news is that, in all likelihood, a $58 part failed that requires a fair amount of labor to get to. The good news is that, in all likelihood, I'm covered by the Zurich warranty I bought when I bought my used car. If the following website is to be believed, my Standard Coverage will cover "all internally lubricated parts including main shaft, ... internal linkages, and bearing." So hopefully this is a no-cost repair to me, as it was to my friend.
While they've got the transmission and engine apart, though, I'm going to likely have them replace the clutch, at my cost. I've got 75,000 miles on the car, and if I can get the labor to unmarry the engine and transmission paid for by my warranty, it seems like smart preventative maintenance to have a new clutch installed.