Hi Merv.
Can't say I've been in a position to build and register a Cobra in NSW.
Theoretically if a LHD Cobra was built and registered/tilled as a 60's Cobra within the USA, then a LHD vehicle of thirty years or older is registrable within NSW.
It must be the same loophole that a lot of car dealers use in order to sell the LHD Porsche Speedster replicas here.
These guys have had a handful for sale over recent years (they don't currently have any right now)
http://www.autostyle.com.au/default.asp
Makes you wonder why a quality LHD Cobra replica is taboo whilst a LHD Speedster appears to be acceptable by our authorities?
Regards.
Steve.