XSLT, Web applications, and "native XML databases"

Gurus:

I am a huge fan of XSLT and document-oriented XML.

I realize this may be slightly off-topic, but I am looking for a
Java-friendly (XSLT-friendly) XML database.

Our data *works* as XML (as opposed to tables), and our particular
situation does not require superhuman performance.

The current implementation is all on the file-system, but I think
we're outgrowing that.

Any recommendations?

Sincerely,

--PETE