Is anyone working on this? Is it possible to implement this before the Playnite 11 beta is released? Wouldn't mind taking a crack at it.

You can add any emulator you want manually without explicit support from Playnite https://api.playnite.link/docs/manual/features/emulationSupport/addingNewEmulators.html#manual-emulator-configuration

@JosefNemec shadPS4 requires a scripted scan to import games automatically. Very similar to the RPCS3 script. I've managed to add support in the source code (I've only tested the import script so far) but I've had no luck adding it manually using the "manual emulator configuration" in Playnite itself.