Not that it's a DVCS, but I remember ClearCase had this brilliant "dynamic" mode which would hook into explorer and simulate a drive with the entire contents of a repo, but only download the files you need when you needed them. I haven't seen that anywhere else
See the "--depth" argument to git-clone.
See the "--lazy" argument to darcs-get.
The "--depth" argument to git-clone, as of 1.7, produces a read-only repository, which rather defeats the point.
This works for me. What's read-only about the repositories that you get?
You're still downloading the whole history. That can be very painful on very large projects.
Or bzr lightweight checkouts?
What's the use case for this?
Quicker checkouts, less data on drive?
The whole history in git can be (and usually is) than a working copy in SVN. Don't get me started on the speed.
The actual checking out goes faster with SVN, nevertheless, because it's so much less data (assuming a decent amount of history). I'm not stating a preference, just facts.
Downloading multi-gigabyte git repos just to work on a very small subset of it.