In the past WaMu has shot its commercials in the LA area. The Northridge branch was where a lot of the in-bank scenes were shot where there are large arch windows. It was also a few blocks from the now-former Southern California HQ. (As an aside, the Circuit City ads are all shot at the store that's about a half-block from the WaMu branch. I stumbled across a shoot one day.)
Below are shots from the commercial. I took pictures of my TV screen but you should be able to see the detail.


