Yeah it would be harder than finding a shop to mount ROssis, for sure.
Any shop that has an old Nordica jig should be able to mount 4frnts though - they are both made by Vist..
Where in Aus are you? If you are in Melbourne, Riderplus is the Aus 4frnt distributor so could probably point you in the direction of someone that has a jig or at least stocks 4frnt.