Is there anyway to replace the nib on a Pelikan level 5?

Pelikan almost certainly won't do it this late in the Level's life. But getting Deb Kinney (google on her name) to do a re-grind to what ever fineness you like should cost only around $50, and her waiting list is very short considering the quality of her work. You'll also get the benefit of about the smoothest fine imaginable, based on my experience with her cursive italic grind (which is probably a much trickier nib.)