Adding to prior evidence that a 13-inch Retina MacBook Pro is in the offing, a new model of the high-resolution MacBook has shown up in another set of online benchmarks. As Mac Rumors details, the new model bears many of the same specs as the model spotted earlier this year, but with a few key differences. Apple has been thought to have a 13-inch version of its MacBook line of notebooks in the works for some time, and the computers are expected to ship later this year.