I've written an article for TechTarget.com about how to bring spreadsheets into master documents, too. You link the spreadsheet to a Writer document, then bring that "dummy" writer document into your master document. It's a hack but a practical hack since big publications often need to combine different document types. There's an approach (even hackier, but useful) for bringing in presentation content, too.
If you haven't read the first article on plain old master documents, read that first.