Microsoft (MSFT) is working on a new line of Surface tablets that includes a 7" model due later this year, the WSJ reports. Given the popularity of ~7" tablets and the fact an upcoming Windows 8 refresh (i.e. Blue) will support them, the news isn't too surprising. The paper doesn't disclose whether the tablets will run Windows RT, Windows 8 Pro, or both - RT sales have been especially bad. The report comes shortly after IDC estimated PC shipments fell 14% in Q1, and a month after it raised its 2013 tablet shipment forecast to 190.9M.