For what it's worth: berg connectors were used for connecting quite some kinds of stuff in the original IBM PCs. Because our modern PCs are still largely "PC compatible", you can still find connectors of the same family on ATA cables, floppy cables, jumpers and CD-drive-to-audio-card cables. The trademark of the Berg connector is the square hole with the square pin.
I would advise against making them yourself because I read it is hell to assemble. You can buy the connectors and little pins (mostly sold in a bag of 100), but you'd also need some special tools as those little pins are allmost impossible to clip on to wire without those tools and some experience.
At one point I wanted to hard-wire my model F XT to a parkbd adapter so I took a similar connector with 2x9 pins and simply cut off 2 rows. If you take an ATA cable (everyone uses SATA nowadays) and split it into two with an exacto knife, you might get the same result. Wire up the right strands, get rid of the others and solder it to a regular keyboard cable. Simple and cheap!