Lenovo's taking the wraps off of its newest ThinkPad here at Engadget Expand, but in fact, the T431s represents more than just a minor spec bump. It's actually the first ThinkPad borne out of Lenovo's latest "clean sheet" development initiative -- an 18-month process that the company briefed me on here. Regarding the laptop at hand, the 14-incher boasts a slimmer, sexier and more understated design, all while remaining very much a ThinkPad. It's being classified as an Ultrabook, yet i
