I agree it's a niche item, but the design seems simple enough, if you want to make homebrew PCBs... it's good practice.
Unfortunately, 17 pin female headers are basically non-existent.
Buy the 40-pin headers, and snip them down. With the male "breakaway" headers, you just snap them in between the pins and you don't lose anything. With the female headers, you snip your way through the middle of a hole with your angle-snips, and you lose that hole. You can then trim the snipped rough edges down if you like. You can get two 17-pins and a 4-pin header out of a single 40-pin stick.