Sounds just like a main bearing man; sorry for the bad news. You should be able to easily reproduce it by revving the engine between idle and 1,500 rpm, as reported on other threads. Here are other 2 YouTube videos so you can hear how to reproduce it:
That's definitely not good news for '08 and early '09 owners (before main bearings were upgraded). Time to take it in. I know this is not a widespread problem, but it's scary to think it could happen after warranty expires, especially for those of us who don't put much mileage on our cars. Will have to seriously think about keeping mine beyond warranty. Good luck, and please keep us posted.