The eagle-eyed gents at Engadget have done it again, and by that we mean scoured the FCC and uncovered something that matters. In this case, it’s the Sony Ericsson Xperia X10 complete with T-Mobile compatible AWS bands, aka WCDMA Band IV. So while this isn’t the first time we have seen or heard this device sporting those bands, seeing it from the FCC just brings music to our ears. So while the jury is still out on whether or not T-Mobile will actually pick this up for subsidy sales, if you hold tight your holiday money from Grandma, Grandpa and Aunt Beth, you just might be able to save up enough to buy it unlocked come 2010.

You can hit the FCC jump for a few images of the exterior of the phone, along with a bunch of other FCC pages I wouldn’t even attempt to read.

Engadget via FCC