That's a great question. We're at an interesting spot where we have to decide whether we want to stick with our basic service and become a company that provides really good hosting and services for small-business websites, or if we want to take on the giant behemoth that is WordPress, while still trying to hold on the the simplicity of the concept. If we go the second route then we'll be building out a plugin system that would definitely make it possible to build something like you described.

In the mean time, our blogging system has the ability to create unpublished posts that are only visible to content editors (individuals that you invite to manage the website). It's kind of a hacky solution but it might work for you.