Thinking out loud: can an adapter ring mate the DK-17M to the F2? Since the DK-17M has a larger thread diameter such an adapter may move the DK-17M too far from the prism for optical purpose. The more I think about this I don't think matting a DK-17M to an F2 is a likely proposition.
Nikon makes adapter rings to mate the smaller eyepiece accessories to the F3HP DE-3 and later threads. I'm unaware of any made by Nikon for the reverse.
Depending on the application Nikon made a DG-2 focusing magnifier. Some refer to the DG-2 as the poor man's 6x magnifier. This would not be for any kind of action or hand holding.
Then there is the DW-2, 6x waist level finder (second link). It's image is reversed right to left like a TLR but the camera can be hand held while using it. The 90 degree, 6x finder (first link, mid page) is most interesting to me. I wonder if it was ever mass produced or if it was only a prototypes? The 6x finders offers a beautiful, bright 5x7 inch like visual image.
Nikon Interchangeable Prisms for F2 Series bodies - Index PageNikon Interchangeable Prisms for F2 Series bodies - Part IIThere is a part III, IV, V, etc. Look for "NEXT" near the bottom of each page.
Something I wondered about but didn't get any farther than thought was adapting a Pentax LX 45 degree angle finder to a Nikon F2 or F3. The Pentax finder might have been a 5x finder?
Dave