None that i am aware of, Every kind of tune that is applied is detectable based on the flash counter and log on the ECU.
I too have been looking for a mercedes approved style enhancement. Possibly something that works within tolerance that could apply the DR520 map or a 507 map to my performance pack plus.
Brabus do the B63 tune, and B63s tune for our cars, I have heard that some mercedes dealers e.g. brooklands do honour the warranty if purchased through them and applied by them.
Hopefully someone can shed some more light.