I've been spending a bit more time working with dxf files and came across a free cad program that seems pretty solid. Allows you to import DXF and DWG files, scale and edit and export as PDF.
To get a 1:1 scale print out of the dxf file you need to first export it as a pdf file on a large format for that the 1:1 version fits on a single page (I use CutePDF or PDFCreator and select a large page size - both freeware programs that install as a printer and allows you to print any document from any program as a pdf). Then you need to get some program will chop up the oversized pdf into multiple A4's. Apparently Photoshop and Illustrator will do this as well as a number of other freeware programs though i haven't tracked any down yet that take a pdf and create multiple pdfs.
The freeware is called A9CAD and you can download it from tucows
I'm sure there are other but this one seems to do what is needed.