OS X Dock Stacks

I came across this video showing the behavior of Stacks in the Dock back in beta versions of Mac OS X Leopard.

The salient difference, for those of you saying "That's the same as my stacks now," is that the stacks are in the application portion of the dock. Not consigned to the Document/Trash/Windows side of the dock, but useful as a true application launcher.

I think this looks pretty cool; the ability to name (and rename) stacks, as well as live-reorder them, seems pretty damn awesome too.

Maybe in an update? 10.5.3 or something?