As with XtremeMac's rubber cases for iPhones and iPods, Tuffwrap for iPad ($40) sounds simple but actually brings atypically nice design to the table. Using a firmer rubber than most of the soft cases we've tested for iPads, Tuffwrap includes both button protection and bezel protection while leaving the ports and speakers exposed -- with relatively small, Apple-sized holes. Though the case doesn't include screen protection of any sort, the back has…