If you execute openerp-server --help :

  Web interface Configuration:
    --db-filter=REGEXP  Filter listed database

If the regexp matches just one database the dropdown list doesn't appear (I use this). I haven't found a way to add this parameter in the config file, though. Additionally, this might worth a try too:

  Security-related options:
    --no-database-list  disable the ability to return the list of databases

Ours is running like this OpenERP Version 8

apache2 proxy settings:

Could not post, because your karma is insufficient to publish linksetc/apache2/sites-available/mydomain.fqdn

<VirtualHost xxx.xxx.xxx.xxx:80 [xxxx:xxxx:xxxx:xxxx::2]:80>
SuexecUserGroup "#1001" "#1001"
ServerName mydomain.fqdn
ServerAlias www.mydomain.fqdn
ErrorLog /var/log/virtualmin/mydomain.fqdn_error_log
CustomLog /var/log/virtualmin/mydomain.fqdn_log combined
<Proxy>
 Order deny,allow
 Allow from all
</Proxy>
ProxyRequests Off
ProxyPass / Could not post, because your karma is insufficient to publish linkshttp://Could not post, because your karma is insufficient to publish links127.0.0.1:8069/ retry=0 timeout=300
ProxyPassReverse / Could not post, because your karma is insufficient to publish linkshttp://Could not post, because your karma is insufficient to publish links127.0.0.1:8069/
# Fix IE problem (http error 408/409)
SetEnv proxy-nokeepalive 1
</VirtualHost>

======================================

/etc/init.d/openerp

#!/bin/sh

### BEGIN INIT INFO
# Provides:  openerp-server
# Required-Start:   $remote_fs $syslog
# Required-Stop:    $remote_fs $syslog
# Should-Start:  $network
# Should-Stop:   $network
# Default-Start:    2 3 4 5
# Default-Stop:  0 1 6
# Short-Description:    Enterprise Resource Management software
# Description:   Open ERP is a complete ERP and CRM software.
### END INIT INFO

PATH=/sbin:/bin:/usr/sbin:/usr/bin
DAEMON=/usr/bin/openerp-server
NAME=openerp-server
DESC=openerp-server
CONFIG=/etc/openerp/openerp-server.conf
LOGFILE=/var/log/openerp/openerp-server.log
USER=openerp

DATABASE=mydatabase

test -x ${DAEMON} || exit 0

set -e

do_start () {
    echo -n "Starting ${DESC}: "
    start-stop-daemon --start --quiet --pidfile /var/run/${NAME}.pid --chuid ${USER} --background --make-pidfile --exec ${DAEMON} -- --config=${CONFIG} --logfile=${LOGFILE} --db-filter=${DATABASE}
    echo "${NAME}."

do_stop () {
    echo -n "Stopping ${DESC}: "
    start-stop-daemon --stop --quiet --pidfile /var/run/${NAME}.pid --oknodo
    echo "${NAME}."
}

case "${1}" in
    start)
        do_start
        ;;

    stop)
        do_stop
        ;;

    restart|force-reload)
        echo -n "Restarting ${DESC}: "
        do_stop
        sleep 1
        do_start
        ;;

    *)
        N=/etc/init.d/${NAME}
        echo "Usage: ${NAME} {start|stop|restart|force-reload}" >&2
        exit 1
        ;;
esac

exit 0

=====================================

/etc/openerp/openerp-server.comf

[options]
addons_path = /usr/lib/pymodules/python2.7/openerp/addons
admin_passwd = adminpassword
auto_reload = False
csv_internal_sep = ,
db_host = False
db_maxconn = 64
db_name = False
db_password = False
db_port = False
db_template = template1
db_user = openerp
dbfilter = .*
debug_mode = False
demo = {}
email_from = False
import_partial =
lang = en_US
limit_memory_hard = 805306368
limit_memory_soft = 671088640
limit_request = 8192
limit_time_cpu = 60
limit_time_real = 120
list_db = True
log_handler = [':INFO']
log_level = info
logfile = /var/log/openerp/openerp-server.log
logrotate = False
longpolling_port = 8072
max_cron_threads = 2
osv_memory_age_limit = 1.0
osv_memory_count_limit = False
pg_path = None
pidfile = None
proxy_mode = False
reportgz = False
secure_cert_file = server.cert
secure_pkey_file = server.pkey
server_wide_modules = None
smtp_password = False
smtp_port = 25
smtp_server = localhost
smtp_ssl = False
smtp_user = False
static_http_document_root = None
static_http_enable = False
static_http_url_prefix = None
syslog = False
test_commit = False
test_enable = False
test_file = False
test_report_directory = False
timezone = False
translate_modules = ['all']
unaccent = False
without_demo = False
workers = 0
xmlrpc = True
xmlrpc_interface =
xmlrpc_port = 8069
xmlrpcs = True
xmlrpcs_interface =
xmlrpcs_port = 8071

=======================

SUGGESTION: DATABASE=.*, new, all, anything, my database (, = or)

and in do_start section the filter --db-filter='^${DATABASE}$' got added

If DATABASE=empty or .*

than the database selector screen gets called

If DATABASE=new, all or anything wording

than the Database Manager gets called to create duplicate etc.

If DATABASE=mydatabase

than the frontend of this specific "mydatabase" gets called

I know... 2 years after... Nevertheless, it could help for others...

I have Odoo 8.0 with the same dilema. I tested your config:

db_name = 'TEST'
dbfilter = 'TEST'
list_db = False

It did not really worked. in fact it worked but the system could not find the database so it showed me the database selector without the selector!... then I noticed the config parameters have no < ' > so I tried without them like this:

db_name = TEST
dbfilter = TEST
list_db = False

It worked!

Took me days to discover that if you are using Nginx, you have to set the proxy headers: http://wiki.nginx.org/LikeApache Otherwise the domain / host is "localhost"  irrespective of what your real domain is!