HI Shane,
I just got my 550 registered yesterday and today it goes in for a complete restoration for the next 5 months! I live in Melbourne and I have been trying to source a 550 for the last 4 years, and you are right - to get DOTARS approval to import one in is a nightmare. There is a guy in NZ who is an agent for Automotive Legends in the states who is going through it all now to bring them into Australia. I was just about to bring one in myself, but it would only be able to be club registered not road registered. By luck I found one locally which was bought in from NZ and I was able to get it road registered. The shape is right, but everything else is wrong - I have half a container of parts coming over from the states to get it to an original 550. Happy to answer any question as I live 550s!
thanks Andrew