a dyson sphere probably wouldn't be too hard to accomplish either, whether inside or out...
for inside, just make a REALLY big model for it, center it at 0,0,0 or wherever, depending on your mission.
for outside, use the same model, hideously far away (or close), and have a bit of the sun shining through.
I'm presuming we have some form of additive or transparent textures (thrusters, etc.) to work with, why not make massive light beams streaming from it?

just a thought, I also might be quite insane. I'll tinker with the dyson sphere model idea after I get done with this planet thing.
silly real life gets in the way

I'd personally push for something similar to halo

Bob
ideas? flames? etc?