It might "work" in the sense that it might not make you ill, but it's very unlikely that Oculus will support it any time soon. They're focusing on pushing the boundary for rendering latency, which current multi-GPU solutions don't handle well.

There are issues with SLI and VR. It works for some people, for others they need to disable all but one card. There's details on the oculus subreddit if you want to search for it.