Yes - a small enhancement, but definitely one we get asked about a lot here at DevExpress...DXperience v2011 vol 2 will introduce the ability to color the background of individual tabs in any skinned paint themes.
Where can this new feature be of use? When used, tabs can be visually grouped by color and you can provide the appropriate visual accent for a specific tab.
Once you set colors for all or individual tabs, they will be automatically merged with the current skin.
Oh - and this feature is available for all controls providing a "tabbed" UI including the following: WinForms TabControl, TabbedMdiManager, DocumentManager and LayoutControl.

Post comments update...For those who wanted to see how this will look with some of our skins...
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