msdn.microsoft.com/.../en-
us/odc_SP2003_ta/html/ODC_SPSCustomizingSharePointSites2.asp.

This article tells you that it is not possible to build a site
directory (SPSSITES) from a copied template  (if that is what you are
doing). You have to edit the original default  template.
Also one more thing I noticed is that the default.aspx of sites  area
has a redirect to summary so you probably want to make the edits in
the summary.aspx and allitems.aspx which is in the LISTS folder  and
sub folder SITESLST.

'm working on copied Site Definitions.
I have to look for another solution then as I have no intention of
touching the default  Defs fearing future upgrades will wipe them
out.

I would think if you want changs to appear for the sites  template, you need to modify those site  definition files.

I thought so too but it is not ON for the site  directory
definition/template apparently. Even customization of any area  site
definitions can only go so far. aspx  pages (access from the "Action"
Menu & "Site Settings") under the layout  virtual directory can not
be branded the way areas are. Some of these pages can be branded
using AlternateHeader. But even that can only go as far. What I
realise now is that branding every single page  serving from a
sharepoint server is not straight forward.

There is a skinner alternative started by Serge van den Oever
available here: http://weblogs.asp.net/soever. Could be applied to
any ASP.NET application you want to put some skin on. I think it is
very nifty that you won't need to touch any Sharepoint files.

It is recommended not to modify the default  area templates because modifications  may be lost by the applications of patches and fixes. Yet you cannot use copied templates for sites  Home, Event Calendar and site  Directory because it may cause “functional problems” as stated in the doco at the URL below...