Hi Tom
You're welcome. If you're going for centralisation then perhaps a server is something you could look at? Bear in mind if all you want is simple file sharing for 10 users or less then the client OS is more than sufficient. Just don't make the hardware acting as the 'server' in that sense a normal workstation with someone working on it. Performance will be much better if you left it as standalone. If of course you want/need access to some of the advanced technologies available in OSX Server then "fill your boots mate!"
I have been known to dabble with OSX Server now and again. The dedicated Forum for all things OSX Server can be found over on the OSX Server Forum:
http://discussions.apple.com/category.jspa?categoryID=96
There are some very capable guys in your part of world who regularly contribute to a highly skilled level to that forum. You could put out some feelers there if you wanted to? In addition Apple do provide a means of finding a consultant here:
http://consultants.apple.com/
I also quickly googled these:
http://www.applecations.com.au/
http://www.atozpages.com.au/contentsatoz/COMPUTER-SYSTEMS-CONSULTANTS/WA.asp
If you were to Google for "Apple Consultants in Australia" you may find more?
Tony