uhm, as far as I know, diskemu can have more than 9 items...I currently have 12 and some lead to other menus :-)
to add a submenu to diskemu just do something like...
1) Goto Submenu
onkey 1 goto sub
:sub
1)menu
2)menu
its very easy, I could post my diskemu.cmd file if you still run into problems...another menu system would be bootscriptor/isolinux