I finally decided to grab an Incase Slim bag, but their site says they're currently not available. That seems to be true a lot of the time with them. Anybody have any idea how long it is before they become available again? Barring that, is there a good substitute? I don't want to pay the high price of some of the other ones that are out there. But is there anything as good, or comparable, at a similar price? thanks!