I keep thinking that somebody is going to take the optical interferometry ball, and run with it.
An example of what a wide-baseline interferometer pathfinder/demonstrator can do. Small mirrors are a lot cheaper and easier to make and to make precise (and keep them precise over time). Of course there is no question that combining the light from multiple mirrors presents challanges that the whopper scopes don't have to worry about (unless you are talking about whopper interferometers like Keck).
'nother example