Sha-Touched Leather was introduced by the expansion, Mist of Pandaria. Sha-Touched leather can be obtained by skinning lower level beast from Pandaria. Sha-Touched Leather can be converted from a stack of 5 to a single Exotic Leather and can be found at starting areas of Pandaria.
See below for places to farm Sha-Touched Leather.
1. Singing Moths, Silverthorn Calf