1. We aren't even sure if it's possible and it'll be months before we even the brightest emulator minds can get anything working to see from an experimental prospective.
2. Why pay a one time fee for an emulator when you can charge a lot of money buy selling the game separately?
3. We can already play them on modern televisions. You hook your Dreamcast's AV cables to your television.
4. If High Definition is your treat then try this up-scaler or buy the HD games off Xbox Live or PSN.
5. Who the f*** cares about OUYA?
*EDIT* This goes in General Gaming.