I have been thinking of using M8 studding connectors rather than a single M8 nut on the z-axis lead screws of my 3D printer. My sense is that the x-axis motion would be more stable, and with two connectors, held together in the same plastic piece, it reduces backlash (but I don’t know how to measure that … it just feels like it; I can feel the backlash in a nut, but not in the pair of studding connectors).
Below is a screen capture of it in Google Sketchup. You can download the SKP file here.
The STL file is here. Basically the connector is just an M8 nut that’s 23.7mm thick.