I was lucky enough to observe Big Ned in all its stages of construction. I think Marks intention was an engineering/artistic exercise with a very Australian feel to it. Obviously Ned is not a practical motorcycle, the lack of suspension would ruin any rider over distance. That massive engine with its rotary valves and cyberpunk brasswork is more an aesthetic expression than anything, but its one that roars.
Some people like fishing, others enjoy carving blocks of alloy into large volume combustion engines.
This is not the first effort Mark has made into engine building. His V Twin drag bike has been around since I was a kid.
Marks monster drag bike is built for a purpose, mainly fast et's and lots of smoking rubber down the dragstrip. It has evolved and always improved. Ill find the Two Wheels magazine article and scan it to the web.