What is the best way to design full vectorial scroll-down menus with SVGT1.2

Hello SVG gurus,

One of the main advantages of vector-graphics technology like SVG should
be to provide "Scalable" interfaces which are automatically resized
according to the screen size.
One of the key interface component according to me is scroll-down menu
wich enable the user to select items in menu and sub-menus which may be
contextual to the current session.

What I can't figure out is : How can I build such menus in a scalable
way especially concerning some text inside a box ?
Do I need to use viewBox ?
What about the font ? How can I be sure that the text is automatically
resized in order to fit the place allocated to the drop-down menu on the
mobile device ?

Vincent