Here is something I noticed while whatching Surface Pro 3 presentation:
At the very end of it, we see Surface Pro 3 and some other Surface device to the left. I added the picture of Surface 2 for reference and as you can see touch cover is quite different from any other Surface models we know. Layout is more compact and centered leaving no place for trackpad.
But when perspective correction applied, it's also become apparent that device have 3:2 aspect ratio just like Surface Pro 3 and 4 rows of tiles also proves it.
I already posted about it in comment here.