I am designing a mezuzah case that will have a scanned image of the mezuzah klaff on it. Can I use the image as is, or are there any words that are inappropriate to be used in this manner?

I have consulted with some prominent Halachik authorities with your question and they allowed the scanning of the klaf of the Mezuza to be placed on the the Mezuza case.However, since the text will be outside the mezuza and not concealed on the inside, caution must must be taken as to one's modesty in the vicinity of the Mezuza. Also, a digital image of Hashem's name may be erased since it is not made to last and neither was it written "b'kdusha. (Rav Lior of Kiryat Arba-in Hebrew counterpart of Ask the Rabbi). Nonetheless, caution should be taken not to do unnecessary erasing of Hashem's name. Furthermore, once printed, printouts of the klaf should be placed in geniza and not discarded.Shana Tova and success in your artistic endeavors.