Ooh, looks like somebody's popular. If you tried to order a Wi-Fi iPad this morning, you might have noticed that the expected ship date has been bumped a week to April 12 and in-store pick-up has been nixed as an option. Seems like the first pack o' Pads have all been spoken for. Just how many is that? There's no way to be sure, but some of the most recent estimates put the number somewhere near a half a million. Yow. [Planet iPad via 9to5 Mac]