Hello...if you get the Eagle software and Fushion 360 software for dev. desktops, you can use the 2 x 23 header, alter it, and see it in CAD format in Fushion 360. It actually has every instance on the BBB and not just the headers, i.e. P9 and P8 are accompanied by many more parts.
Eagle has a BBB related section installed by default. Then, you would add it to the Fushion 360 software to come up w/ this or your own idea:
You can even alter the components if necessary.
Seth