Hotmail comes to mind but the big challenge is getting the colour right.
I did a system using tabs and we had some speed issues. Every possible tab had been created by the graphics guys and these had to load. There was even a mouse over version.
So I cut the left and right sides off one and a teeny wee strip to act as the background and created the following
<style>
/* set up .tabs so that you don't have to code too much */
.tabs TD {}
.tabs TH {}
.tabs A {}
.tabs A:hover {}
</style>
<table class="tabs">
<tr><td><img src="left.gif"></td><th><a href="opt1.php">Option 1</a></th><td><img src="right.gif"></td></tr>
</table>
I can't actually remember if I differentiated between TD and TH or if the use of the <a> was enough. I have some cool sites for manipulating classes and styles linked at http://property.digitalrice.com/