Rhodesy, you can already do that by changing Default Object Color (project settings / ctrl+d), Corona conforms accordingly (meaning - it respects the Color set).
Hmmm, am not sure, but it might be possible to use cinema's own Material Override module with Corona engine?
For starters it would just need to be exposed when changing engines, for first iteration custom materials would suffice, after (if it goes well) Preservation could be adapted to conform with Coronas channels... just a naive thought
edit:
Oh... yes! it works already (also include/exclude), you can set it with standard/physical engine & then switch back to Corona ;)
for channels will investigate further