The latest version is 2008.07.26 Just renaming the ebuild to youtube-dl-2008.07.26.ebuild worked for me. Catch: the -b switch (best quality, getting an mp4 file) didn't work for me in the new version. Reproducible: Always
As Aggelos is away, I've taken the liberty to do the bump. The -b option works fine here, by the way.
I got an answer on the -b switch from the upstream: "Some videos do not have a high quality version available and may return 404." So there was no problem.