Presently i am doing the same thing i was thinking of any other possible solutions. I have read the citroen uk case study where they have mentioned about how they have done this .
http://www.microsoft.com/casestudies/case_study_detail.aspx?casestudyid=4000003851
Relevant excerpts
To help increase manageability and efficiency, Dot Net used Office SharePoint Server 2007 to develop screens that Content Administrators use to automatically manage banners, videos, or images that appear on the sides or bottom of some site pages. Citroën wanted to be able to specify which banner could be inherited by a particular site or pages, so administrators could place the same banner on numerous pages without having to define it multiple times. Dot Net developed custom fields in Office SharePoint Server 2007 to allow administrators to define a banner, and then specify which pages would inherit that banner, including time and date parameters.
i dont know how the above things are done.
Can somebody let me know