I have worked with breadboards for my entire adult life, 30 years actually, and when I got into 3D printing I dreamed of one day soon being able to make my own breadboards.  I imagined that with 3D printing's ability to create almost any shape, we could make breadboards of almost any shape.  Well, in the past 24  hours I just did it!  At the moment the fit is a little loose so I used tape to secure the Proto-pasta conductive inserts (grabbers) in place, though with a bit more fiddling that should not be required.  I tried to use a small sample of BlackMagic3D graphene filament for the grabbers and ran into issues that prevented me from using it.  The key to making it possible to print the grabbers with today's technology is to use every other horizontal hole position as extra space for the grabbers, and to rearrange the grabbers rotated by 90 degrees.  With this approach the breadboard becomes about twice as wide (horizontally) and is the same length (vertically).  See the STL images to "grasp" what I mean by that!  :)I still need to measure the node resistance, and this sort of thing is rich with potential for exploration so I used wiki mode so that you can mod the description and the files with improvements.  Even if node resistance is a bit large, more and more conductive and stronger filaments are coming out now, and with care and an appropriately set up printer you can print with filament thirty times more conductive than the Proto-pasta filament I used, so the choice is yours.  I chose Proto-pasta because it was the quickest path to getting the job done.  Next up:  more breadboards!  You and I can YouMagine all sorts of breadboard arrangements!  Arduino vehicles and robots with structure electronicized, back-to-back breadboards, breadboards wrapped around a sphere or company logo, etc. are all possible.  Have fun!  Lesp.s. I have measured the node resistance at 3 kOhms, which can be improved significantly with design to probably 1k, then using graphene filament we get it down to 30 to 50 Ohms or so.  Graphene is tough to print though, so it depends on your requirements.