Ivan Minic of Pixelita Designs has released a new theme called Two-Tone. Features include tabbed navigation, javeascript show/hide bar at the bottom for the three column "sidebar" contents and a User Control Panel. Sorry, this theme is not currently widgetized; once some widget-related issues are sorted out, look for a widgetized version toward the end of September.
You can view the theme and download it here:
http://wordpress.myblogthemes.com
Joni Mueller