I wasn't suggesting Renderman For Maya mainly because....Poser  content and RfM sort of work against each other. Specifically PRman / RfM prefers NURBS and subDs over polygons, and texture maps should be square;  it's only when you start digging deeper into its functionality that you will see speed gains. Global illumination is a perfect example because at first the workflow appears very cantankerous; but you can do all sorts of crazy things like caching your raytrace calculations, as an example.  If you wanted to try this workflow, you could download evaluation versions of both Maya and RfM which are fully functional but watermarked. 

I was basically referring to any Renderman compliant renderer, specifically those that run off the command line. There are many to choose from: Pixie, Air, 3delight (free with DAZ studio BTW) and of course PRman. Export RIBS from Poser, use a third party app to edit and attach shaders (which could be done by hand), import RIBs into Rman compliant renderer.

I'll second the comment of procedural shaders; they don't transfer.