I don' say it's the perfect way, but this is my way.
Text only in four successive steps.

Using Acrobat to save the PDF as a RTF file (without images)

Using OpenOffice with a 9x12cms model to insert this RTF file and save

Using either
- OpenOffice to export as a PDF in PRS format (don't forget annotating meta-data with PDF Info or another program).
- calibre to convert to lrf, mobi or Epub

Copy in your reader
Results on a text book are pretty clean.
As you could infer from it, I am still looking for a perfect solution dealing also with images.