Is there a way to round corners on material level? Is there a shader that can be used on material level that will give the effect of round edges when assigned to an object? I'm not looking to increase the mesh density, I remember in 3DS Max, Mental Ray, round corners is an option that can be enabled in material, so the object's sharp edges will "look" like smooth, without changing the object's mesh, is there a way to do this in Cycles?
A straightforward solution has been added to the most recent Blender distributions (after the released version of 2.79b, so you must download newer updates of 2.79b, or 2.80 Alpha, from https://builder.blender.org/download/ to enable it).

There's a single node (Input&nbsp;>&nbsp;Bevel) that fakes bevelled normals. Of course it won't change the geometry, so it doesn't look great from too close, but it can enhance pretty convincingly the specular/reflection at the edges.