XslFormattingObjects is part of the ExtensibleStylesheetLanguage family.
As at 2004 it is still obscure and is known to be difficult to hand-code. However it is said to be do-able via the XsltLanguage. And then the Open Source Apache project has this wonderful Formatting-Object Processor (FOP) that will turn an XSL-FO file into ElectronicPaper, a printable PortableDocumentFormat (PDF) file (but some say PdfSucks).