Many sites (including this very one use the Shortcuticon feature.

How about integration of that as a setting for the theme ?

You mean the icon displayed in the browser? the "favicon"?

yes

The problem with adding that is in the link to the favicon you need the url of it, there is no way for the theme designers to know all that information.

The link information for a favicon would be

<link rel="shortcut icon" href="http://www.yourdomain.com/forum/Themes/default/favicon.ico" />

something like that.

However a place with some of the code could be place, but you will still need to code the rest.

The favicon is also something you rather just upload to the server root..not set trough any script?

uploading for sure as you need the url, but i thought more about having passage in the template where it gets put in with the url given in the possible configuration entry just like it is done with the Logo which is being placed in the header.

thus in the Theme Settings have a

URL of Favicon - Field

and in the template you got something like

Att. No actual code just examplatory
<code>
<?php
          if ( $ThemeConfig['faviconURL'] ) {
                    echo "<link rel="shortcut icon" href=$ThemeConfig['faviconURL'] "
          }
?>
</code>

Reason is the Theme stays maintainable be the SMF/TP  facitities as it is a standart link section
entry if wanted.

Ah, I forgot..the link in the theme.

If that works it can easily be set through text-field in the theme, in "current theme settings" for example. Different themes could even have different icons then.