There have been rumors flying for YEARS in the machine arts community that some lucky fabricators were holed up in Australia somewhere building vehicles for Mad Max 4 under extreme secrecy with insane budgets.  We do know that they’ve been working on the film since 2003 and have had numerous setbacks including a bloom of pretty little wildflowers all over their post apocalyptic setting.  The director says they have built over 150 vehicles.

Supposedly this is a tanker from the film.

http://www.republikein.com.na/politiek-en-nasionale/algemeen/mal-rygoed-in-die-woestyn.143786.php