What I have done so far is:
- Conversion of sgml files to valid xml syntax with a perl skript. I failed to use 'osx' or 'spam'.
- Conversion of these xml files to Docbook5.x format using xsltproc and Docbooks xslt-migration skripts.
- Creation of html files using xsltproc and Docbooks xslt skripts.
- Creation of fo files using xsltproc and Docbooks xslt skripts.
- Creation of pdf files using fop.
- The conversions needs less than 10 minutes on a Intel i5 processor.