While hardly current, Lima did offer their Southern Aurora sleeping car painted in all the varieties of colours the steel Overland cars had up to the date of production of the models.
This of course only covered the sleeping cars, although the lounge cars used a sleeping car body.
I have a set of sleeping cars and lounge car in the plain silver livery that was used on the standard gauge until the elimination of overnight services.
I've been waiting a long time for a Steelink BL to haul them (Powerline promised one at least twenty years ago).
But sleeping cars were available in Regal Red with grey roofs lettered for "V&ANR" and Great Southern.
CR pattern dining cars and power vans were available painted to match.
In the immediate period following the change to standard gauge, when the train was operated by AN alone and hauled by CLP class, CR dining/lounge and power and baggage vans in plain silver were used with the red and silver sitting and sleeping cars.
This is an option if you can't afford a trainbuilder set (or don't have powerful enough locomotives to haul the heavy brass cars).
I have a Trainbuilder H class that I could use on red and silver cars but two B class would be more believable...
There may be some Lima cars still available second hand.
Frateschi make cars that are a reasonable facsimile of the sitting cars and at a stretch, the baggage cars, but these would need to be painted, and (of course) they are models of Brazilian broad gauge Budd cars and have fluted roofs. Frateschi sleeping cars are a worse option than the Lima cars, which at least have the correct windows for Overland cars buiilt after 1966.