If your users are in /home and you're not willing to modify your filesystem layout much, you could simply export your /home as readonly nfs share and mount it to /var/www/users. something like that should work in /etc/exports: /home -alldirs,ro 127.0.0.1
$ mount_nfs -o rw 127.0.0.1:/home /var/www/users now you can ignore the fact that apache is chrooted. Don't expect read performance to be the same though.
