[Lynne]

Easy way to remove those navtabs and leave the bottom bar is CSS:

#globalsearch {display:none;}
#navtabs li, #navtabs li a.navtab {display:none;}
#navtabs li.selected, #navtabs li.selected ul li {display:block;}
.navtabs {height:0; padding: 0;}
.navtabs ul {top:0;}
.navbar {height: 26px;}

Hard way is to rewrite the navbar template.