The unlocked Samsung Galaxy Nexus isn't the only hardware device that Google is offering for sale through the Google Play Store: it's just added accessories as well. At the bottom of the page for the phone three different items are listed. The vehicle dock, HDMI desktop dock, and the landscape pogo pin-enabled dock are priced at $54, $49, and $54 respectively, and given how difficult some of the accessories were to come by in the phone's early days the additional distribution channel is welcome. Then again, they're only compatible with the GSM version of the Galaxy Nexus, so if you're looking for accessories for the Sprint or Verizon variant you'll need to look elsewhere.
When Google rebranded its selection of online stores as Google Play it was focused primarily on digital goods: apps, music, books, and video. The addition of the Galaxy Nexus, and now hardware accessories, seem to indicate that the company has slightly more ambitious plans in mind. Of course, it's been rumored that Google will be selling the forthcoming Nexus-branded tablet direct to consumers, so we wouldn't be surprised to see the hardware selection grow even further in the months to come.