We'll have to see. I got the model for the HSV E1 front bumper from EFFalcon, but I haven't imported it yet. The models from CommoConfigurator don't quite line up with the Forza models, so I have to adapt the parts onto the Forza mesh before using them. If this works out, and if I have sufficient demand, I might ask him for the Commodore Calais and Omega meshes too.
The one difficulty I have had is getting a Pontiac G8 GT (not GXP) front bumper. This isn't super important, but it would be a nice touch, as the non-GXP front bumper gives a different look to the front of the car. Unfortunately, I can't find one of these anywhere.
As far as the wagon, you'd probably have to ask Marco. I am not good enough at modeling to do what he did with the Ute - he basically grafted the entire front end of the G8 from the doors forward onto the Ute body. The CommoConfigurator VE wagon model doesn't have interior, so it would also be a question of adapting the rear interior from the G8 to fit.