The following tables should illustrate some advantages of the different alternatives. Note that heavy table magic is used... ;-)

Using Alt I

Basic structure:

tavi_header: logo, page title, toolbar_top, hr
tavi_body
tavi_footer

If shifted to a two column layout, this could be goaded into

tavi_header: logo, page title, toolbar_top, hr tavi_body
tavi_footer

Where of course the tavi_footer could be shifted out to either side, but the page title would be cramped in the left column, and the hr should be made invisible as it's no use at the bottom on its own. The toolbar_top should/could be styled to be displayed vertically without problems. The logo is also restrained within the tavi_header, but that might not pose as a problem.

Using Alt II

Of course the basis option could be used, but the interesting aspect arises in the two-column layout.

tavi_header: logo, page title, toolbar_top, hr page title(2), tavi_body
tavi_footer

As the page title has been duplicated one could easily add the following to the css-file:

 div.tavi_header h1 { display: none; }
 div.tavi_body h1 {display: block;

If wanting the basic structure, this statements are reversed. Still one has the issue of hr's being not so very useful. But it's rather easy to have a proper two-column layout. It's also possible to have a three-column layout by using the same trick to the tavi_footer div. Thusly having a layout like:

tavi_header: logo, page title, toolbar_top, hr page title(2), tavi_body tavi_footer

Whether this is easily maintained for different layout I'm not sure, but it's possible... And with proper selection of elements places in tavi_header and tavi_footer (see TaviTodo/NewPageElements) it could be made working great. But I guess if one want to use a three-column layout, then all layouts should be based on three-columns.

Using two-columns layout it's easier to maintain style sheets for both single columns layout and two-column layouts at the same time.

Using Alt III

Here it's possible to place every div just where you like them. So doing something like the following is possible:

logo - Page title
hr
tavi_toolbar_top, tavi_footer tavi_body

Or maybe you want to place the tavi_toolbar_top as a floating div always remaining on the same position on the page? It's possible, although not entirely cross-browser.

Surely, more examples could be added, and please do so if you are so inclined. But please do so with a certain degree of truthfulness as to whether it's actually possible using the given alternative.