It would not be difficult to create large "special" units on paper, but in order to fill in the numbers we will have to ease the selection criteria so that these units no longer consist of the very best soldiers that we have...... and the results will reflect this.
Yes the standards would have to be lowered to create larger special units. Instead of increasing the standard of the special forces we should instead increase the standard of the conventional army. This would result in a massive drop in numbers however you could then create a full time "army reserve" organisation, or a "National Guard".
This full time army reserve could have even lower standards than the current army increasing the size of the army. However this wont lower the standards of front line units that see combat in any way. The full time army reserve can also train with the part time army reserve units. As the full time army reserve would be less demanding and easier to get into it may encourage part time army reservists to become full time.
The full time reserves would only have to deploy overseas in emergencies. Any full time army reserve soldier can be promoted to the full time regular army by training to pass the required tests.
Currently we have (i've included a skill level):
200 special force soldiers - 100% skill level
25,000 full time troops - 70% skill level
15,000 part time reserves - 30% skill level
We would then have:
200 special forces soldiers - 100% skill level
10,000 full time troops - 80% skill level
20,000 full time reserves - 50% skill level
10,000 part time reserves - 30% skill level
As a result the full time troops have a higher skill level as weak links are placed into the full time reserves.
Soldiers can quite often move up and down between full time troop to full time reserve, depending if they pass the fitness test, want action, or want to settle down at a reserve training facility in their region. Some may prefer to be a leader in the full time reserve rather than a follower in the full time troop. Some may prefer the opposite.
Equipment wise, the full time army reserve can get all the old vehicles, kit and weapons from the full time front line forces to play around with. This saves money. Also as you now have a smaller leaner front line army bringing in new equipment and standardising it will be much simpler.
It could work well.
With Australia getting fatter keeping the high level of standards will become difficult. You dont have to be that fit to drive a supply truck so if shit hit the fan the full time reserve units can do all the secondary/logistical stuff.