3D viewer for ply, stl, obj, Lwo, glb, cob, scn, c4d, etc (binary & ASCII) with conversion & thumbnails would be helpful.  Maybe use something of Sourceforge etc to make it quickly! Or from Blender or BforArtistists.
Sounds like a nice idea to complete the Viewer capabilities of FileVoyager.
Not on my priority list as I have higher priorities, but added in my whishlist.