Won't work. Requirements for everlasting life are too complex. After all, science has barely begun to accept the idea that there is a soul and spirit. Even if the physical body has been kept alive forever, will the connection between it and the soul/spirit always remain, as well? We are far from understanding things like this, and they may not even be something we can understand.

Besides, when the connections are weakened, there are evil spirits that want to get in and take over both body and soul, right?