We know that the Samsung Cetus is on its way to AT&T this fall packing Windows Phone 7, a 4″ AMOLED display, and a round-corner design. But what is this device, posted by a developer on Twitter? It’s different than the Samsung Taylor which has been deployed to thousands of developers around the world. It’s possible that it’s a more mature reference design from Samsung (since the Taylor was pretty much an Omnia HD under the hood), or it could be a new WP7 device headed to market. It has sharp edges, what looks to be an AMOLED display, a circular indentation surrounding the Start button, plus no front-facing camera. We’ll keep digging as we try to learn the true identity of this new device.