shayne

This plugin blocks everyone but the admin from accessing the WordPress Admin. It will redirect the user to your 404 error page if they do not have access to the admin. Your theme will need to have a 404 error page setup.

ST Admin Protection

This plugin blocks everyone but the admin from accessing the Wordpresss Admin

Kostas Vrouvas

This plugin adds the WordPress menu from the admin sidebar under the {site-name} menu on the front-end WordPress toolbar.
Feedback is much appreciated.

Front-end Toolbar

This plugin adds all WordPress pages from the admin sidebar under the "site-name" menu on the front-end.

ST Admin Protection vs Front-end Toolbar