Because I'm not planning to give another FMX talk this year I started showing some screenshots of my current rendering research/tests on my render forum:
In this case I took a Radiance scene and imported it with my own Radiance importer into Blender, exported it with my own Blender to Arnold (BtoA) exporter to Arnold's .ass scene description, and imported it with my custom Maya translator (import and export) into Maya (on OS X).
The second screenshot shows the same pipeline (import into Blender, export to .ass, import into Maya). If re-exported from Maya you will end up with exactly the same picture rendered by Arnold but as you can see the new Cycles renderer (shipping with the latest Blender releases) matches already very well the output of Arnold (if color correction etc. is handled correctly and some pitfalls are avoided). The full post can be found here.
At some point my experiments will go into a direction where I can store a scene and materials independently of the renderer(s) being used and to switch between different renderers (and algorithms) on the fly.