PDF Module, PDF full pageheight or full scroll
I did something similar with print module , it also may be posible with PDF module. Override print--pdf.tpl.php file to fit your needs, copy print.tlp.php file from print-module directory (or look for a similar file in pdf module), paste it in sites/all/themes/your-sub-theme/templates folder. in line 100 is print $content, there add a css class "myclass" with higth=100%; done!.