BisonTech

This plugin replace WP default admin/login/register page. 
The technique used is pretty brutal but the best currently possible, the plugin replaces the modified files automatically. 
To make the plugin run the web server must be able to write to the wp-admin directory. 
more info @ http://www.bisontech.net

LogoReplacer

This plugin replace WP default admin/login/register page.

Emilien Laborde

Wp chart generator makes your life easier to create graphics on your blog. With a single management in the back office, you can create as many graphics as you want. Management of these charts is based on custom post types.
Create a graphic is simple : 
<ul>
<li>First clic on \”add a new graphics\”</li>
<li>Then enter your data</li>
<li>Publish it and a shortcode will automatically be generated</li>
<li>Finally copy this shortcode and paste it into an article</li>
<li>Go to the article and TADA a graphic appeared</li>
</ul>
 Enjoy guys with this plugin.

Wp chart generator

This plugin allows you to easily manage graphics on your blog

LogoReplacer vs Wp chart generator