Great operaguy. Yes...you can tweak textures and lighting more in carrara. Soft shadows should be easy. You have alot of lighting options...save presets when you get ones you like(looks like colored lighting).May try irradiance or hdr also to see if they will work for you. I haven't done too much with those so I don't know about speed. I do know GI is for accuracy...not speed.

No need to think outside the box....
    Just make it invisible.