Hi Shane,
depends on what format you need for the Ipswich layout.
If you need the route complete with tracks and landscape already done, some are in production but completion date is a very long way away, maybe years, due to the high level of detail. See the "Brisbane CityTrain - 800x600 pixels" thread for work in progress.
If you are able to make your own landscape using the Trainz surveyor tools and thus only looking for the raw DEM format with accurate landscape such as hills at the correct heights / locations, along with the road and rail locations correctly marked, than try
http://forum.victrainz.com.au/index.php and look for the DEM request thread which will point you to the storage folder with the DEM routes.
That Victrainz thread will also mention the very recently released DEM only Ipswich route, including the new Richlands branch. Using the various separate DEMs in that storage folder you can do QLD from the steam era Tweed Heads / Coolangatta area north to Gympie and west to Ipswich and the Brisbane Valley line etc.
You note Melbourne as your location so you may see some interesting VR routes in the storage folder of that extremely generous Victorian group. Registration is free.
Cheers
Peter C