To the OP, JBD tune isn't available for CA residents.

Let's assume, just theoretically speaking obviously, that one would delete EGRs and DPFs, and SCRs and all those goodies that save us from cancer and all other hibigibies.

Let's also assume that you can have zero exhaust smoke at idle.

Would it be possible to make a tune that is undetectable to OBD scanner used by smog centers that checks for readiness of the various emission components?

That might be possible, but considering the extremely small market i doubt someone will spend 1000s of hours programming and testing. Esentially all the monitoring will have to be emulated inside the DDE. Emulators for the sensors would be the more viable option in the Arduino era.
Me and my father are currently developing Arduino based emulator for the N62 engines SAS. N57 is much more complex, but nothing that cannot be fixed with a few hundred hours development :rofl: