Well Surface 2 Pro is imminent. MSFT event on 23rd. Rumored to ship with release of windows 8.1 on oct 18. Haswell chip 8gb 8 hrs of battery life. Bring it!
If you REALLY want to go that route, there is a thinkpad helix already. http://www.pcworld.com/article/2046...le-but-expensive-ultrabook-tablet-hybrid.html