Rare is the cringe-worthy case release from XtremeMac, which has generally been right on target or close enough with past designs to merit at least some praise, but the Play-Through Sleeve for iPad ($35) is an obvious miss: a neoprene sleeve with a hole cut in the face for touch-through iPad screen access. The problem isn't so much the 2004-vintage concept of building the screen protector directly into the case, but the quality of the plastic XtremeMac…