The Little English Halo Blog
Halo 4 Franchise Director Frank O'Connor has suggested that the Halo 4 Limited Edition has started to sell out. GameStop in the US have ran out completely and Amazon have removed it from the site, several bricks & mortar UK retailers have stopped taking orders too. If you haven't placed your pre-order yet, now may be the time to do it.
Since then, Amazon has reduced the price of their limited edition to £59.99, meaning they're now the cheapest place to get it and have a generous selection of pre-order DLC.
http://www.littleenglishhaloblog.com/2012/09/halo-4-limited-edition-starting-to-sell.html