medusa, sorry to reply so late. (I'd no internet access for a couple of days, which felt like eternity by the way).
When do you think you'd like to own a croc Birkin? Is this for 2008? If it is, I suggest you call your H store to find out what are the croc colours offered at the July podium. (not the same croc colours are offered to every H store, some colours offered to Europe may not be offered to Asia) And choose from the July podium offering, so your store can help you get a croc birkin. It really is no point wanting a colour that is not offered, as it may take forever or never to arrive.