Create SharePoint 2010 ribbon button programmatically w/o feature XML

Question

I have to create a SharePoint 2010 ribbon element (tabs, buttons, groups, etc.). Is there a way to create such elements via the SharePoint API without using custom actions?

Edit: I've just found the possibilty to add elements like this (link):

SPRibbon r = SPRibbon.GetCurrent(Page);
r.RegisterDataExtension(/* XmlNode containing ribbon element code */);

Another workaround would be to append a custom web control and append dynamic controls to this "placeholder".

Is there a way to create elements without using xml nodes?