Vitalii Kiiko

(Eng) Adds a “Maintenance Mode” page to your site (sending a “503 Service Unavailable” status). Includes MailChimp mail subscriptions.
(Ukr) Плагін додає сторінку-заглушку типу “На реконструкції” (надсилається статус “503 Сервіс недоступний”). Включає форму підписки на ел. пошту з допомогою MailChimp.
<a href="http://demo.uni-theme.net/" rel="nofollow ugc">Live demo!</a>
Features:
<ul>
<li>Used custom fonts with cyrillyc characters</li>
<li>Social service integration</li>
<li>MailChimp e-mail subscription form</li>
<li>2 themes available</li>
<li>Custom logo</li>
</ul>

Uni-theme Maintenance Mode

Florent Maillefaud

The WP Maintenance plugin allows you to put your website on the waiting time for you to do maintenance or launch your website. Personalize this page, pictures and countdown with:
<h3>Features</h3>
<ul>
<li>Choice texts colors and fonts</li>
<li>Upload logo picture</li>
<li>Upload background picture or pattern</li>
<li>Countdown</li>
<li>Custom Code Header for Analytics ready</li>
<li>Social Networks ready</li>
<li>Customize CSS</li>
<li>Insert for shorcode (Newletter or Contact form)</li>
<li>Enable “503 Service temporarily unavailable”</li>
<li>Choose access by Roles and Capabilities</li>
<li>Choose access by ID Pages</li>
<li>Choose access by IP addresses</li>
</ul>
wp-maintenance.pot file available

WP Maintenance

Create and customize your maintenance page

Uni-theme Maintenance Mode vs WP Maintenance