It is possible to create WebRibbon programmatically in order to create WebRibbon dynamically based on the user who is logged on. In my opinion, the structure can be defined in xml file.

Hope this helps.

Is there an example of this?

I tried to create a very simple sample of WebRibbon. The WebRibbon only consists of a single of WebRibbonTab and a single of button such as shown in the following snapshot (for reasons of simplicity, the ImageUrl property is not set).

This structure of WebRibbon will be stored in an xml file, for example: RibbonData.xml.

<WebRibbon runat="server">
  <RibbonTabs>
    <WebRibbonTab Name="Opportunities" Text="Opportunities"
                  Description="">
      <Groups>
        <WebRibbonGroup Name="Records" Text="Records">
          <Items>
            <WebRibbonGroupItem Name="New" GroupItemType="Button"
                                Text="New" MinSizeState="Medium"
                                GroupName="" />
          </Items>
        </WebRibbonGroup>
      </Groups>
    </WebRibbonTab>
  </RibbonTabs>
</WebRibbon>

In order to load the ribbon structure from an xml file, we will read and check each of the xml elements and attributes. After that, we will programmatically create the corresponding object based on the value defined in the xml.

I enclosed the sample page as attachment. Please have the attached sample evaluated on your and let us know whether this helps or not.

Should you find that this concept is suitable for your scenario, I may be able to help proposing this as built-in method of WebRibbon to the WebRibbon development team.