I know nothing of mental images/Autodesk’s plans, but we can hope that something this cool ends up as a rendering option for SI.
Here is info on iray:
http://www.mentalimages.com/products/iray
The release video (incredible stuff):
http://www.youtube.com/watch?v=TQsXualxLVs
Recent press release:
http://www.mentalimages.com/news/detail/article//mental-image-29.html
It would seem that by the next SIGGRAPH in 2010 (normal announcement date of 3D vendors new software), most vendors will have had time to do an integration of mentalray 3.8 and possibly iray.