As previously stated, root is root. What you may want is an encrypted file(s). Here is a wrapper using Bcrypt
#!/bin/sh
[ "${1##*.}" == "bfe" ] && BASENAME=${1%.bfe} || BASENAME=${1}
BASENAME=${BASENAME##*/}
MD5=`echo "$USER:$BASENAME"|md5sum`
echo "${MD5:0:32}
${MD5:0:32}" |bcrypt "$1"
This one allows users to encrypt their own files, but only uses an md5sum of the user name and file's basename for the "salt".
If you wanted to get really paranoid you could use some pseudo-steganography with bcrypt's -o option and >> some-large.jpg (I wrote a partial example here: ... just as proof of concept)
Another way to do this would be to embed the file in a c program so that it only spits out the data if getenv(USER) matches your admin account name
of course none of this will permit root from moving,renaming,deleting... only from editing in a useful way