Yep, that's AMD's forthcoming mid-range GPU, the Radeon HD 4850. It's a single-slot design, and it doesn't look all too dissimilar from the current 3800-series. Our sources state that AMD aren't allowing its partners to adjust the reference design at launch. If indeed that is the case, every Radeon HD 4850 will initially look like the above, with the various partner-provided derivatives arriving later on.
This sample seen in the wild would suggest that the next generation GPUs are only a few weeks away.