It would appear as though Lumia 710's at Nokia Canada HQ are powered by Windows Phone Tango - 8773 in this case. Reader Julio sent a Lumia 710 back to Nokia for repairs and found that they actually sent a replacement device, but it's running the latest versioin of the Windows Phone OS. Perahaps a sign of an impending update?
We previously looked at Tango on the Lumia 710 with our own Daniel taking the loaded ROM for a spin. We stated that Nokia is busy at getting Lumia Windows Phones updated with the Tango upgrade, and this is further proof that such efforts are taking place. We're still looking at an imminent release for Tango, so stay tuned for more information as it surfaces.
Thanks, Julio, for sending in the photo!