Yeah, I was referencing light field displays. I think we'll eventually see an attempt at a commercial VR unit with light field displays, but I think it's about a decade away before the first one goes on sale. They also have the added difficultly of needing even more renders from the GPU.
The lense adjustment would still mean that objects at different distances would still all be at the same focal plane, but that the focal plane would change depending on what you're looking at. I bet it's probably good enough for most people, but I've never heard of it before so I'll look into it.