CMS driven by XML that is easy for clients

Hello,

I am looking for a CMS solution that I can offer my clients that will make it easier to update info. I am using primarily flash and XML, does anyone know how I would:

A: Start creating a CMS from scratch or a template similar to this: http://www.wa007.com/projects/wa007cms/

or

B: Purchasing a CMS solution that will provide me with the same thing as the example above.

Some names of software of some form of direction would be greatly appreciated.

P.S. I am new here, please be gentle.
**
THE MIGHTY DIM SUM**