L B, if your concern is that if you create the master page in VS, it's not customization by content editor, you can create a page type with editable fields for the component you want the editor to control in the header and footer. Then in your master page, you can use API to get value from a Config page using that page type to render the managed content. Other component in the header/footer should be dynamically generated by other controls (e.g. repeater or hierarchical viewer for navigation).