Yup, for sure it's out in the wild in some locations. This was a T-Mobile owned corporate store, so perhaps it's a dealer only thing. They had 5 of them, 2 were left when I grabbed mine.
Ones on ebay scare me still, they have the back side contacts like the 8900 has in the picture.. Couldn't find the cradle on t-mo's website, but the part number listed on the bubble wrap holding the stand is: ASY-14396-011
If you google search it, looks like it's available at a few sites already..