I was able to test an open-source project that provides a homebrew replacement for the Sony BKM-129x RGB/YPbPr input card used in select Sony BVM monitors: The BVM D9H & D14H and the PVM 9L2. & 20L5 (secondary slot). This card was made by reverse-engineering the original and using an Arduino Nano to emulate the software. I tested both RGB and Component Video signals across all supported resolutions (240p-1080i) and all worked perfectly without adding any interference or lag.
Hopefully other people will become interested in this project and help migrate it to different BVM’s that could absolutely use the support. For now, the developer doesn’t plan to sell it himself, but one person is currently make a small, group production run for anyone interested.
And here’s the previous project mentioned at the beginning of the video: