I recently released a free theme for Twitter Bootstrap 3 called CardeoStrap. It’s a flat theme, fully skinned with all the Bootstrap components you’ve come to love. The colour palette is taken from flatuicolors.com and there’s a demo available at cardeostrap.cardeo.ca.
The following components have been fully skinned: Typography, Tables, Forms, Buttons, Dropdowns, Tabs, Pills, Navbar, Breadcrumbs, Pagination, Pager, Labels, Badges, Jumbotron, Alerts, Progress Bars, Thumbnails, Media Object, List Groups, Panels, Wells, Modal, Tooltips, Icons, Collapse, and Carousel.
Each component has been broken out into an individual LESS CSS file to allow for easy customization. There is also a
lib.less file for configuring global variables like colors, fonts, margin, padding, as well as some mix-ins for CSS3 features like rounded corners. I hope you find the theme useful, comments are welcome.