@Lloyd - You can see an HTML website dual horizontal menu's here:
http://demo.artisteertoday.com/2menus/
For joomla try these basic instructions:
1. Create your template and export it to joomla.
2. Install to joomla and make it the default.
3. Create a new module position in the templateDetails.xml file. <position>menu-2</position> ( this can be any name you wish)
4. Insert this code in the index.php file. <?php echo $view->position('menu-2'); ?> ( insert right above </header>)
5. In joomla, add the main menu to position-1
6. create another menu and select position menu-2 (or whatever you called it)
7. In the template.css you need to position this menu. ( you can position wherever you want.)
example:
.menu-2 {
margin-top: 170px !important;
float: left;
margin-left: 85px !important;
}
8. Then in the 2nd menu under advanced options/menu class suffix enter this:
art-hmenu menu-2 (a space needs to go before this statement)
Keep in mind some templates will need additional tweaking.