It's more than a theory, but with the costs associated so far, it seems to me that it's not a question of developing the technology; it's a question of figuring out how to make it workable in financial terms. We know that we can spend astronomical amounts to do it. Specifically, have there been any indications that the costs are going to somehow come down so that it becomes actually feasible?
On April 2nd, 2009. See this statement in context.