Someone may have always done this so sorry for any repeat. The attached pic is a demonstration of using Bryce 4's panarama render mapped onto the inside of a sphere to create a crowded scene. The left side shows the final render while the right show the scene in line render mode to show how few props were used to make the scene. This was rendered in poser. The process is very simple though you do need to create a higher poly sphere than what Poser gives you and you need to map the sphere with spherical coords. Also the render should be fairly high res. The map for this was 2000x1500. I'm setting up a city now and want to see how that will render. If that looks good then making a crowded city scene would be very simple.