The whole instrument thing is interesting. If the holder of a RPC with a cross country endorsement applies to CASA for a RPL they will receive an RPL with a cross country endorsement and will have zero logged hours of IF (IF not being part of the RAA curriculum).
If on the other hand, the holder of a RPC without a cross country endorsement applies for a RPL and then wants a cross country endorsement on their new RPL they will have to do a minimum of 2 hours dual IF, one of which must be in an aeroplane. (Ref 61.500)
In answer to the OP's original post, it would appear to be more cost effective to first get an RPC with cross country endorsement, use it to get an RPL, then find someone to do a bit of conversion training with in say a C150, then pass a flight review. They may then however find themselves in a spot of bother, if the reviewing instructor elects to bring out "the hood" :-)