So at a time when most companies are scrambling for a prime seat on the green bandwagon, why not a company-branded wind farm? John Deere Wind Energy is building an eight-turbine, 10-megawatt wind farm in Panhandle, Tex., that is scheduled to open in May. Steelcase, the big furniture company in Grand Rapids, Mich., has committed to buying the farm's entire output of renewable energy credits