At one time, not so very long ago, I made the nfsd work on the Hurd. However, it was not terribly reliable. On my GNU/Linux machine I mounted my Hurd machine's root directory on /mnt/hurd, and ran something like:
find /mnt/hurd -type f | xargs sum > /dev/null just to see how far it got. The poor nfsd hung about 1/2 way through the file system. It's not clear what this test shows, except that the nfsd has some problems. But, you can mount file systems and it will work for awhile. Unfortunately, other things got in the way, and I haven't looked at it since just before Christmastime. As far as I know, the daemon is in the same state it was when I last looked at it.
