yio, it's not available yet.
On another thread someone mentioned they saw it in a B&N store and it was great.
I don't understand your screenshot question.
When you connect it to your TV it'll show you whatever is on your Nook screen on your TV in High Definition.
If you have a High Definition TV then I would assume it fills the screen.
It works well for 1080p and 720p videos such as Google Play vidoes and 720p youtube vidoes. 480p youtube vidoes, web browsers, and powerpoint presentations lose resolution on the TV as compared to the Nook screen. A fix to allow setting the resolution is expected in the next system software release according the the support rep I spoke with today. Release is probably by the end of 2013.
I use mine all the time with getting movies from Crackle. Have no problems with the cord and do not have to take HD+ out of case to use the adapter.