I think these types of things would be really really cool to do with TG2, but as long as it is still very difficult to accurately put something into a TG2 scene I think this is a no go area.
You can export pieces of terrain and then "glue" your model to the terrain and make it look perfect. Then export the model and import it back into TG2.
All nice and well, but then comes the "impossible" part: matching the model back to the terrain.
I remember mohawk doing a suspended footbridge in an image and he also complained it was tedious to get it properly integrated.
Martin