bq. (Unless it’s possible to embed SVG in a document that only complies with the HTML rules”¦)
Quick experimentation shows that Mozilla 3.5 doesn’t display the SVG unless the file ends in .xhtml (when loaded locally) or served as xhtml+xml from the server. In either case, the document has to follow XML syntax. Also, if I don’t add the xmlns=“http://www.w3.org/1999/xhtml” attribute to the <html> element, paragraphs show up as inline rather than block elements. YMMV with Opera or Safari.