I can see three ways:
1. swap CoronaLight with standart spotlight and your projector map as gobo. (pros - easy to set up, very precise projection, cons - non physical light, volumetric cone might take longer to get noise free )
2. swap geometric cone with extruded gobo shape (pros - volumetrics gets rendered faster and looks very good, cons - harder to set up, shadow is inverted, and it looks like there's no way around this :[)
3. place gobo shape inside the cone, behind the light (pros - ?, cons - gobo shape becomes very blurry with distance, light and gobo rig must be encased or placed away from view)
Sorry, no examples this time.