I don't usually keep the stereoscopic renders as they're just for fun, but I happened to find this test render from a very early stage of a scene. If it doesn't work, turn your glasses upside down.
The problem with depth in Octane's 3D is that both of the virtual cameras converge on the focal point, and increasing the distance just moves them apart whilst continuing to look at the focal point. What we need is a second controller to change the distance of the cameras without changing their rotation (i.e. they're not locked to the focal point). It's that which allows increased amounts of depth, because the further you move the cameras apart, the more depth you get, while having the cameras focused on a point just means that everything in front of that point 'pops out' and everything behind it gets pushed back.
So basically, if we could just move the cameras apart without changing their angle, we can get the same depth you get with other programs, and controlling where the cameras look just changes which parts of the scene go back and which parts come forward.
Right now we can only get very subtle depth in Octane because once you start to move the cameras too far apart, it starts to ruin the 3D, because each camera begins to look at a completely different image and they no longer work together.