I think that the best option out of this if possible is to have a scandoubler that outputs at an HD resolution such as 720p or 1080p at 50hz, achieving 100% compatibility with all PAL TVs. Then the picture is displayed in 4:3 format framed, with pixel size multiplied for a few times as long as it fits in the displayed resolution!
For example, if a game has 200 pixels in height resolution, the picture when displayed in 720p would be multiplied for 3... displaying 600 pixels in height. The remaining 120 pixels will be split - 60 pixels top and 60 pixels bottom frame. In case 1080p picture would be multiplied by 5 and you'd get 40 pixels on top and another 40 pixels for frame.
Who is going to do this
