We never thought we'd see the day, but the Sony Ericcson Xperia X1 (we were getting ready to dub it "The Unicorn") has made it through the Federal Communications Commission's testing, reports Cell Phone Signal.

And as we suspected, AT&T should be the lucky carrier with this one, given the 850/1900/2100MHz bands.

Also confirmed are two versions of the phone - the X1 for Europe, and the X1a for the U.S. And while you can buy an unlocked X1 and use it on T-Mobile, remember that TMo uses the 1700 MHz band for 3G, and you won't get that with this device.

The silver paint scheme that we've gotten to know remains. As an added bonus will be a black skin, too. No word on if it's version- or carrier-specific.

No word yet on pricing, carrier-subsidized or otherwise. Also no word on an actual U.S. release date, or whether any of the delay rumors are true.

Hit up Cell Phone Signal for a few user guide pics.

Thanks, Marco!

Update: Here's the link [via Giz] to the FCC testing, if you're into that sort of thing. It's OK. We won't tell.