This looks like a great, ambitious but still possible concept. I did not see something like that in a long time.

I hope you find the team and the technology that you need to make that reality.

From my personal view I think C4 engine could do the job for you. The new ambient space feature creates ambient occlusion like radiosity lighting even on quite weak hardware (because it is some kind of static lighting, still able to illuminate your moving vehicles dynamically) and it can even look better with additional dynamic lights.
There is a project called "World of Subways" (made with C4) that proves that something like this is possible.
http://www.world-of-subways.com/index.php?id=172

But we can talk about more details directly. I will just contact you.

Regards,
Frank