Customizing the WordPress Backend

Hello guys,

I’m in a project where we would use WordPress as a directory, so every subscriber would have an author profile, and the capabilty to write posts and modify his/her profile, shown as a custom template page.

The thing is, we would need to turn the WordPress Admin screen in something very different, with gradients and almost a tubular feel.

How could I modify dramatically the WP backend ? I now where the backend’s CSS are, and which .php files I should modify, so my question is if I have to little by little modify the core, or there’s some easier way.

I know there are some nice plugins to give a new esthetic layer to WP, but in this case I would be interested in turning the inside in almost completely different, keeping some essential fields, and hidding the rest.

If you have any idea regarding the easier way, or, by default, about some other CMS which would allow me a quick backend modification, I would like to know your thoughs.

Thanks very much,