New Zealand designer Jono Williams built his otherworldly Skysphere clubhouse in around 3,000 hours from $50,000 in materials. No bathroom, but it has plenty of great amenities:
Mobile App Remote Controlled
Fingerprint Entry Motorized Door
Refrigerated, In-Couch Beer Dispenser
Fully Solar Powered with management system
Miracast Projector
Wireless Sound System
Computer generated voice dialogs
360 Degree Viewing Window
Custom Built Queen Size Bed
Dimmable Colored Mood LED Lighting
High speed point to point wireless internet
Central Ladder
Rooftop Starview Platform
Natural Light Portal for column
The Skysphere (via MAKE)