I don't think Linux permissions tools really work that way ie actively disallow a specific uid.
It's more a case of only actively allowing everybody else.
You could look at netgroups+NIS http://www.linuxtopia.org/online_boo...g-exports.html
That page also mentions RHEL NFS can use acls; might be worth a try.
Maybe try putting that user in his own primary group eg guest/77777777, don't add any other secondary groups to him and and never allow any group/file to have guest group ownership (apart from his home dirs).
Also, of course set world ('other') perms to '---' everywhere you can.