Octane Render
I wonder if this is worth looking into. Looks like it would need some other software to get from Revit into Collada format or something but hmmm...
"With current GPU technology, Octane Render can produce final images 10 to 50 times faster than CPU unbiased render engine..."
"FILE FORMATS
Import of wavefront OBJ format with parameters and material import
Import supplied vertex normals or calculate them via supplied smooth groups
Import of Collada .dae format**
Full support for RenderMan RIB format for animation environments**"
Their Gallery is amazing.