How about implementing such a thing for two-SIM phones?
Essentially, it should look like an option inside the ambience’s menu: instead of just ‘ringtone’, it might look like ‘ringtone - SIM card 1’ and ‘ringtone - SIM card 2’. Additionally, there might be two different ringtones volumes for each. The rationale behind this proposal is that, if you use a SIM card for personal stuff and another one for work, you might want to identify if a call is coming from your employer or from a friend without even having to look at your phone. Even more important, on weekends for example, you might want to set the volume for your ‘personal’ SIM to a medium level, and mute the volume for the ‘work’ SIM card - this gives you the possibility of being available in case something is seriously wrong at work, but without being stressed about the possibility of a loud incoming call from your employer.