I'm also looking into high-ticket niches at the moment here is what came to my mind so far:
- real estate (especially luxury houses)
- commercial real estate (tens or hundreds of millions)
- Jets, Airplanes and Helicopters
- Luxury cars
- High-roller casino
- Luxury travel
- enterprise software
- legal services
- headhunters
- government contracts (defense, building, procurement)
- boats