While not exactly a custom build, this Roccat keyboard uses optical switches: https://en.roccat.org/Keyboards/Vulcan-TKL-Pro https://en.roccat.org/Keyboards/Vu

While not exactly a custom build, this Roccat keyboard uses optical switches: https://en.roccat.org/Keyboards/Vulcan-TKL-Pro https://en.roccat.org/Keyboards/Vulcan-TKL-Pro Similarly, there's several Razer mice that use optical switches for their main 2 buttons. ("Optical" here being a switch that is tripped when an object breaks the beam of light)