Hi Zuts.
you may find that there are difficulties getting some scopes from the US as there are contractual agreements between Meade (possibly Celestron) and suppliers in the states and Australian suppliers.
I would also suggest thinking very carefully about purchasing anything large from overseas, simply from a warranty point of view when you need to return to the supplier.
This is especially true for delicate objects like lenses and mirror components
The reality is though that buying something large like a full setup from OS doesn't really save you a lot of money in the long run. I bought a Losmandy G11 mount from Optcorp (they are great to deal with) at what I thought was a good price. Buy the time it hit my front door and delivery, GST and Customs were added, I saved about $250. Hardly worth it really considering any warranty issues that may come up in the future.
If you are after something like an AstroPhysics mount and a Takahashi then you mightn't have much choice (but you can get them in Australia at a price
) but Meade and Celestron large items, well......I'm not saying don't do it, just have a good think about it first.
If you are after small items though like eyepieces and focuser and CCDs (under a $1000 Aus) then by all means go for it.