http://solareclipse.net/ Whipped this up tonight. It's based on the general table-as-tabs concept that the 6.6+ control panel uses, though with a few giant implementation differences.
First, view the HTML for the tabs. Just ids and a few classes. That's it. No onclicks, no nested anchors.
All the behavior for the tabs and the styles are added when the page loads.
The main advantage with this approach is that it's very easy to add a new tab - just two new cells with the right ids.
The 800 pound gorilla of DHTML has free reign in the 6.6 control panel. Because everything's generated by a script, there was never any need to keep the code light and agile.
Feel free to examine the code and implement something similar. Post here with questions/comments.