I haven't read through all the replies but I purchased an overseas Britax model (Safe And Sound maker) via Amazon and had a friend ship it over so that DS can rear face for much longer than the seats in Australia allow for (oh - and even with the shipping, it cost much less than the equivalent seat here - and the seat I purchased is an excellent seat). Technically, the seat doesn't meat Aus requirements, but I've researched it's safety and am willing to risk being ticketed as DS will be so much safer rear facing for longer than any Aus seat would allow.
I was just wondering how that works with insurance as I would look at getting a seat from OS if we are lucky to have another baby by the time DS needs turning in his current seat.