There's nothing better than a lkeside lunch of fresh-caught fish, but that usually means packing along a heavy, fire-blackened skillet. Purcell Trench solves this problem with a line of beautifully made, stainless-steel grills, far superior to the aluminum of most pack grills. Their fast-cooling Streamside Traveler measures 17x51/2 inches and weights a scant 5.8 ounces. Other sizes and models, plus custom designs, are available. All come with a light, durable carrying bag. About $42.