Superstructure markup

I everyone !

I didn't found any subject about superstructure markup in the archive
of our list, so here it is.

I most of the sites that I create, I have the following main parts :
- skip links list ;
- a header ;
- a general menu ;
- sometime a 'local' menu (if the gen menu makes it not) ;
- a footer.

What about specifing the corresponding markup (remember the HTML 3.2
<menu> : http://www.w3.org/TR/REC-html32#menu), on the base of the
WHATWG work : http://www.whatwg.org/specs/web-apps/current-work/#the-nav

But I think that a scope attribute could be needed, who's values could be :
- global for the entire site ;
- page for that page only (TOC, for example) ;
- section, for a part of the site (identified by her root element URL ?) ;
- etc..

(see http://www.w3.org/TR/html401/types.html#type-links).

The scope could used by UA for caching issues, reloading previous
rendering of an element with the same scope value, and so skipping
render computation for that element.