We have recently discovered that our Chromebooks now support wifi single sign on correctly and manage vlan switching from a guest / provisioning wifi ssid to a user ssid using 802.1x correctly!
This is great as so far this is one of the only devices where I have seen this process handled cery gracefully with no input from the end user.
Background: We utilize Google Apps Directory sync to keep our users/ou's in sync with Google Apps from our AD structure, we also handle password sync between AD and Google Apps, and also have 802.1x user based authentication (PEAP MSchapV2) in place. We have set the device to pre-autehnticate to our guest/provisionsing network using a common username/password, and then set our chromebook user settings to use the username variable for the 802.1x authentication.
The result: A user powers on the chromebook and the device has limited network access, and can login a user to their Google Account. As soon as the login process completes the device disconnects from the guest network and automatically connects to the student SSID utilizing the username/password used to login to the chromebook.
In the aruba logs I must say this is the most gracefull SSID / re-auth I have ever seen, and the device never seems to get stuck on the old VLAN (like I have seen on so many windows machines...)