The online documentation was contradictory at the outset, so it took us a few days to figure it out, but the new iPods have been “decontented” (see below): the low-end model, now 20 GB, has always lacked a dock, remote and case; but the 40-GB iPod now only comes with a dock, and not a remote or case.
Presumably, removing the remote and case from the US$399 model was one of the ways for Apple to cut prices without cutting profits overmuch. I imagine that their market research suggested that if they had to remove accessories, the remote and case would have been missed more than the dock. (That would be my sentiment, but I don’t presume that my preferences are somehow indicative of the whole, unlike many commentators.)
“Decontenting” is an apparently common practice of the auto industry: increase profits by removing standard features and making them extras, rather than raising the sticker price. (See the bottom of this page.) It’s best, of course, if it’s a feature that the customer won’t miss overmuch — i.e., the cost of including it outweights the benefit derived from including it — otherwise there’s a general hue and cry.