This is great science, and I'm sure we will learn a lot about brains, but there is no way a simulated brain will have any kind of consciousness without a simulated body as well. Without a body and an environment to interact with, the brain is like a computer program with no data to run on.
Experiments have shown that if you yoke a paralyzed cat to another cat and let it experience a complete array of visual inputs, the yoked cat will still be completely blind. Interactive embodied experience is the foundation of cognition and consciousness. A brain in a vat is as empty as a computer without i/o.
It would be interesting to have a full-scale simulation to learn about how activation propagates, how different systems interact, yada yada yada. But until you give it a body there won't be any ethical issues.