I'm currently about to enter a web design contest at my school along with a friend, and together we wanted to create a Wordpress blog theme. But so far... none seem to just be barebones, without and CSS Code, just the PHP code already there. Just if you know of a "blank" Wordpress theme... thanks.
UPDATE : I do in fact know CSS and have had some experience with Wordpress, I just wanted to know if there was any theme MEANT for that type of use that anyone knew of. (Thanks for the answers!)
Try the default one. You'll want it there for reference to the templating function calls within in. Also look at the CSS file as the template details (which appear under the admin) are scraped from here.
You'll have a better start first analysing this theme, and then removing or editing portions you don't need.
You should just create one from scratch. All you need is a plain text editor and some type of graphic software( like Photoshop or GIMP).
There are tutorials on Wordpress.org. A simple Google search should do.
Realize that designing themes is a fairly simple task, but editing the php is the hard part. However, very little php is needed for a basic (though less functional) Wordpress template.
Just pick a template (default one?) and delete the CSS file (and any image files). Strip any ugly, unnecessary <div>'s and <span>'s which may be present. You now have a blank template.
This site is an excellent Wordpress theme tutorial. It guides you right through from scratch about how to build a theme, which parts go where, which files generate what parts of the page, etc. It's really in depth and a fantastic resource that doesn't seem to be well known enough!!
SandBox was designed specifically for this... it provides good semantic markup with practically no styling. The best approach is to install SandBox, then create your own "child theme" that references sandbox as its template. Instructions for this can be found in the WordPress Codex.