Since the launch of the Moto X, there have been two available storage options: 16GB and 32GB. For some users, 32GB just isn't enough without an SD card slot (seriously though, what are you guys doing with your phones?). Fortunately, it looks like Moto may be gearing up to launch a 64GB variant of the X, which looks to be available with a $100 price bump over the 16GB version.
Unfortunately, we have no idea when this may be available – maybe Moto will announce it soon, maybe not. Perhaps the company will wait and offer this as part of its X+1 launch, as a means to satisfy users who would otherwise be content with the original X and more storage.
Like with all leaks of this nature, we'll have to wait to find out.