Some very nice architectural walkthroughs by the Indian studio Real Works.
Sivaprasad Velayudhan writes:
We are a 3D Visualization Company based in India. We have completed a few Architectural Walkthroughs using only Open Source Software.
Please find more Walkthroughs here.
Modeling, Shading, Lighting, Rigging, Animation, Editing all in Blender. Gimp used for Texturing. Renderer is Blender Internal.