[memco]

That looks quite a bit more spartan than these chara corder keyboards I saw in use recently: https://www.charachorder.com/. They have a QWERTY keyboard with chording firmware (and a chip for custom keyboards) to try corded input for those who want to experiment without going all in.

[xupybd]

You can also use something like plover on an N key rollover keyboard http://www.openstenoproject.org/

I think that has more to it as it's not just chorded but has a steno dictionary as well. There must be a way to turn a standard keyboard into a chorded one?