Before anyone gets too excited about the 777X have a look at the timeline. It's not going to be available for at LEAST another 7 years.
Boeing spent 2010 and 2011 honing its concept for the three-member 777X-family aircraft as a competitive response to the larger Airbus A350-900 and -1000. Boeing envisages the concept's firm configuration being established in 2015, flying in late 2017 or 2018 and entering service by 2019.