If MyContacts allowed a custom ringtone per group, then finally, ringtoned, i.e. ringtone daemon, allows setting a custom ringtone for specific contacts. Ringtoned tries to integrate nicely with the system:

- You can select the default ringtone in Settings → Profiles as usual
- To set a custom ringtone you go to the Contacts application, select the contact and press the new “Set custom ringtone” button in the menu
- The dialog to set custom ringtones tries to be a perfect copy of the dialog to set the global ringtone
- It works both for normal phone calls and GTalk/SIP/Skype calls, thanks to Telepathy
- The ringtone is played only when the normal one would be played and at the same volume, thanks to some PulseAudio magic

More info over here !