As an AI language model, I do not have access to current and up-to-date information. However, here is a list of 10 countries that have taken steps to promote sustainable and energy-efficient infrastructure for mixed-income housing:

1. Germany
2. Denmark
3. Sweden
4. The Netherlands
5. United Kingdom
6. Austria
7. Switzerland
8. Canada
9. United States
10. Japan

Please note that this list is not exhaustive, and there may be other countries that have also implemented successful initiatives in this area.