After reading these posts again it is evident that the
SEO theme was lost or side stepped by some.
Be careful where you place your links, as links to sites that dio not follow your site theme or contain some of the words in your key word base set may often carry negitve juice which will cause great losses as this is implemented in a large algorythm which is re-itterated many times untill it reaches a limmit at which point your scores are alocated.
this means any negative "juice" is a real problem which needs to be avoided at all costs
so be aware of where you place your links, and where you send that link to,
By designing a single page within your own site that has a similar key word base set to the theme of the designed site, and having the link go to this page, you will do a lot better if you do reaaly want to place a link in the footer of your clients page.
You can cross link this page and even refer back to the designed site in different areas, which will help both your pages and your clients pages. this does however need very carefull evaluation of the clients site, and the make up of your site.
You may need to include such a page for more than one client for the search engine to notice this, but you do need to be very careful of negative "JUICE" as some times it is hard to find the right remidie, and your own internal page link value will drop rather fast once you start to get any negative "JUICE"
bottom line is be careful where you place your inbound links.