I am a publisher and... advertiser. It means that every day I need good fonts for my job. So I started to make fonts by myself – more than 10 years ago. Some of my fonts a based on existing ones with free license. But I am fond of Bulgarian Cyrillic glyphs model, so I changed them including this model in my fonts. But if you prefer to write Russian Cyrillic, or Serbian, or Macedonian – not a problem. OTF offers a way to change the model: either by using locl features or by Style Sets.