Dick..
Big Country...little radar coverage. You have tried (and made an absolute dogs breakfast) to get US type of airspace implemented in Australia, the critical shortfall in your plan was that we dont have a fraction of the radar coverage in Oz as the US have over the pond.
Simple solution: ADS-B installed in aircraft to make up the shortfall in ATC surveillance.
If you want to be separated from other aircraft efficiently, get this piece of equipment installed, from the costs you are talking about it will only take a few trips at correct flight levels to recover the costs.
As an ATC, I will tell you right now, I dont give a flying rats ass if aircraft are flying at their non planned levels if it is a requirement for me to have the aircraft separated, ADS-B equipped or not. I dont care if it costs them $1000 bucks an hour in fuel, as long as it doesnt cost them their lives.
If you are not flying under surveillance ATC separation standards become rediculously large (5 miles radar/ADS-B to upto 50nm co altitude) as it is impractical to launch aircraft out of terminals on the same route (into non surveillance airspace) 50nm apart....vertical separation needs to be applied.
Dick...get your aircraft equipped with the best technology available to ensure you get to your destination on time and on budget.
This is not ATC's problem. This is not CASA's problem, this is your problem, and a lot of it is of your own making because of you banging on about airspace.