<p>Has anybody got any suggestions for a custom tabcontrol implemented in C# and which adheres to these criteria:</p>

<ul>
<li>Allows the tabs to be placed along the side of the control.</li>
<li>Tab text must read horizontally.</li>
<li>Allow custom colouring.</li>
<li>Open source or no cost.</li>
</ul>

<p>I prefer not to get my hands dirty with <em>ownerdrawing</em> if a solution already exists.</p>

You probably don't have a need for this anymore but anyone else who stumbles upon it might find it useful.
I found this tabcontrol on CodeProject it is also very easy to Draw your own tabs with it, they even give you a example on the site.
Y(et)A(nother)TabControl
A couple more tab controls.
TabStrip Control
TabStrips: A TabControl in the Visual Studio 2005 way!