I don't think that NX gives you direct control over the DPI, but I think it has your other options covered.
colors: black on white (monochrome)
output text: polylines (converts fonts to lines)
NX output is vector based for unshaded views generated from the model (I think shaded views do use rasterization, but I'm not 100% sure). Of course, if you have any raster images in the drawing, these will be output as raster images in the PDF.