Redmond's "major announcement" may be just around the corner, but mum's the word on Microsoft's lips. Still, that hasn't kept the rumor mill from churning, and the latest is just in: Microsoft's next slate may be built in-house. According to sources from The Wrap and AllThingsD, the firm is planning to introduce a Microsoft-built tablet, undercutting the efforts of third-party builders to more directly compete with the iPad. Rumors flit back and forth between the slate running the ARM optimized Windows RT, the
