Where's my Newton? -- If your daily newspaper offers a comics page, you may have guessed that Doonesbury author Garry Trudeau already has his Newton MessagePad, and you may be jealous! Not to worry; even though virtually all dealers in the "regional roll-out areas" such as Boston, New York, and San Francisco have run out of MessagePads, and some early purchasers have managed to resell their units for huge profits, the nationwide roll-out appears to be on schedule for Labor Day. According to Mark H. Anbinder, several dealers have reported hearing from Apple that they will receive their introductory shipments this week.