I figured out how to turn one of the tabs red using a css snippet and the function below. Just it only works when the tab is not selected..what else would need to be added to get it to be all red all the time?
<mx:Style>
.tab1 {
fill-colors: #e91116, #e91116;
}
</mx:Style>
<mx:Script>
<![CDATA[
private function setTabStyles():void {
taskNavigator.getTabAt(4).styleName = "tab1";
projectNavigator.getTabAt(4).styleName = "tab1";
}
]]>
</mx:Script>

