Wanted: A Very Minimalist Theme

I'm porting a website to Drupal and want a very minimalist theme that I can just wrap around it, while preserving the original look but still preserving access to Drupal functions (like create content). This is part of a transition towards Drupal.

I'd like a wireframe that might just take 50-100 pixels tall on the header and footer, and only 10-20 pixels of width on each side. My ported website is around 730 pixels wide (fixed width), and I want to keep the total width down to less than 800 pixels for low-resolution screens.

Inside the wireframe I'd like to use my own CSS (not have it overruled by drupal or a drupal theme). Outside the wireframe I'd like Drupal's CSS to rule.

How can I do this?

Is there a very minimalist theme I could use a starting point (I looked at the existing ones, and they weren't minimalist enough)? Or a site I could look at that uses this approach - so I can see how they do it?

Note: I'm using Drupal 5 (RC 1).