You will be able to replace this menu with your own events and then you can draw your custom menu using commands (just like RPG_RT RPG Maker 20XX). You can summon the main title menu, so it follows you will be able to summon any other menu too.
This is how people did custom menus in 2003 anyway, so all I have to do is give you the right commands to make it easy and fun vs. 2003's picture mangling. You've seen how individual GUI elements can be drawn and they will be in whatever current system graphic mode.