Rules:
- It's allowed to pushback to the edge of the runway with your back wheels.
- You'll MUST have all wheels from the ground before running out of runway space
- Minimum allowed fuel load: 25% of total
My tries... all succesful till now

KLU KDC-10, SIA B777-312, KLM Lockheed Electra, Aeroflot Il-76

USAF C-133A, Aeroflot An-22, Again KDC-10, SIA A340-500