It can easily be accomplished by adding a HTML module to your skin and not show the skin container, and then adding code similar to below. (of course you need to change the images and links.

<!-- Begin Header Actions Table -->
              <table id="DNN_HeaderActions" cellpadding="2" cellspacing="0" border="0" height="100%">
                  <tr>
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://www.dotnetnuke.com/tabid/125/default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_downloads.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_downloads_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_downloads.gif'" width="46" height="44" alt="Downloads" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/125/default.aspx" class="DNN_IconLink">Downloads</a>        
         </td>
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://www.dotnetnuke.com/tabid/702/Default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_directory.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_directory_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_directory.gif'" width="46" height="36" alt="Directory" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/702/Default.aspx" class="DNN_IconLink">Directory</a>
         </td>
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://www.dotnetnuke.com/tabid/795/Default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_forums.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_forums_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_forums.gif'" width="51" height="39" alt="Forums" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/795/Default.aspx" class="DNN_IconLink">Forums</a>        
         </td>
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://www.dotnetnuke.com/tabid/824/default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_modules.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_modules_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_modules.gif'" width="37" height="40" alt="Forge" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/824/default.aspx" class="DNN_IconLink">Forge</a>
         </td>
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://www.dotnetnuke.com/tabid/825/default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_blogs.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_blogs_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_blogs.gif'" width="45" height="36" alt="Blogs" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/825/default.aspx" class="DNN_IconLink">Blogs</a>
         </td>
   <td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>

                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="51"><a href="http://marketplace.dotnetnuke.com"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_mp.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_mp_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_mp.gif'" width="48" height="43" alt="Marketplace" border="0" vspace="3"></a>
             <a href="http://marketplace.dotnetnuke.com" class="DNN_IconLink">Marketplace</a>
         </td>
        
                       <td class="DNN_HeaderActionCell" align="center" valign="bottom" width="47"><a href="http://www.dotnetnuke.com/tabid/1111/default.aspx"><img src="/Portals/_default/Skins/DNN-Minimal/images/icon_careers.gif" onmouseover="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_careers_over.gif'" onmouseout="this.src='/Portals/_default/Skins/DNN-Minimal//images/icon_careers.gif'" width="44" height="43" alt="Careers Program" border="0" vspace="3"></a>
             <a href="http://www.dotnetnuke.com/tabid/1111/default.aspx" class="DNN_IconLink">Careers</a>
         </td>
                  </tr>
              </table>
              <!-- End Header Actions Table -->
       </td>
          </tr>
      </table>
      <!-- End Header Table -->