This is a great idea! For those of us that actually want a damn accurate watche that can set itself without having to buy Seiko's Astron watch at $3000-5000 up, it's what exactly I've been looking for.
I would buy it for that alone.
I just came back from Switzerland's Schaffhausen, the home of Swiss watchmaking and saw watches up to $10,000 each that lose 20 seconds (and up) a month.
If Seiko think there is a market for people willing to spend $5000 on a GPS watch, I think Sony will have a winner if the time is right.