"PDF-Printer" on amiga or exporting PDF? I am not aware that this is possible but would do be interested. You can print as postscript file and this convert f.e. on windows but that is not amiga-only then.
Most of the DTP related apps I ever used on amigaos (which ever vintage) had Postscript print abilties, so does iBrowse IIRC and certainly the like of OWB do.
ImageFX can "print" to EPS, which is invaluable when used in combination with Wordworth as wordworth then passes the high quality EPS straight through, and does create it's own grayscale version.
I added this functionailty to print to PS / EPS Sketchblock to replicate that workfow, but you can also output direct to PDF via PIL. (Python Imaging Library)
AmigaOS has PS prnter driver that can also save psoscript direct to file, for printing from those apps that don't do postscript output themselves.
To convert to PDF simply use ghostscripts PDFWrite "device"
Another problem... at least the software I use to design "printable" documents supports different versions of PDF, not possible on amiga I guess.
I've not yet come across a situation wher the version of PDF I *created* was important. I have couple of times come across PDFs from else where that the current OS4 versin of ghostscript doesn't work on. I used linux to sove that hickup.