This bug still exists as of dpkg-1.10.9, I just got caught by it while trying to run "dpkg-repack --root=/sd0s3 ...", which just calls "dpkg --root=/sd0s3...", which then does the wrong thing.
As a workaround, I just chroot-ed to "/sd0s3" and ran "dpkg-repack" from there. -- Jeff Sheinberg
