I am building a DTD for a tool that will modify only attributes. I do not care if it is DTD compliant. I am looking to have ANY element be able to be a child of any other element. Just to keep the parser from modifying the data set. Currently I have any entity that contains a complete list of elements and allowing ((zero or more) of each) zero or more times.
I think you probably could make all elements an inclusion of root, but yuck.
Example of yuckyness...
<!ELEMENT root - - (all|child|elements)* +(all|child|elements)>