XML DOM and Postgres

Has anyone experimented on using Postgres and XML in one fashion or
another:

      (1)  XML documents stored as text with indexed keywords to recall
the document.  The document would be stored as a single text blob or
sequence of lines.  XML flagged keywords could be index to allow
searching for particular XML documents.
     (2)  I have seen some questions regarding "tree" storage in
Postgres.  head, nodes etc.. Is anyone storing XML documents in DOM
format into Postgres.  Is it wise or efficient to do so?
      (3) Keep XML documents in separate files.  Store keywords, and
file name in Postgres and index keywords.

I have been toying with a few methods but it appears XML is a square peg
in a SQL round hole.  If anyone has an approach that they are using I
would like to hear about it.

Is there an Open Source ODBMS out there, that someone is aware of, that
would be a better fit for queryable persistent storage of XML DOM
documents?

Regards,

Ray Racine
ray@malema.com