Does anyone here know how to reproduce approximate AO with the node compositor?
I want to use this technique to try to reduce the noise of cycle renders.
I think you’ll want to look at the bilateral blur node 
If you add a normalised depth pass to the normal pass and use that as the key, it’s pretty good at removing noise, but will blur your textures.
Thank you Casio! This is exactly what I was looking for! More people should now about this awesome tool, especially now, with everybody experimenting with cycles.
Can you provide a quick demo shot and node screen grab?
Bilateral Blur Basic Setup
I just recently ran into the texture caveat mentioned. It works great, however, for geometry.
Most interesting! Is there any workaround for textures?
I wouldn’t think so (limiting texture blur) as the noise is not an overlay, unless you can render it to it’s own layer and blur it there?