10 Templates is far too many for one project. You should be using 1 or maybe 2 templates maximum for site wide structure. Add embedded CSS code for page specific styles.
Use Server-Side Includes for site wide menus. If your web host doesn't support SSI, find a better host.
CSS Menu Systems
Project Seven Responsive Tabs
http://www.projectseven.com/products/tools/tpm2/tutorials/responsive/i ndex.htm
Pop-Menu Magic2 by PVII (DW extension purchase)
http://www.projectseven.com/products/menusystems/pmm2/index.htm
jQuery Superfish
http://users.tpg.com.au/j_birch/plugins/superfish/
jQuery Mega Menus http://www.javascriptkit.com/script/script2/jkmegamenu.shtml
CSS3 Dropdown Menus
http://www.red-team-design.com/css3-dropdown-menu
Nancy O.