The overall plan is to build an instrument that has approximately a 74-meter total aperture (perhaps sixty 8-meter mirrors) in a segmented design. It will take full advantage of adaptive optics and the latest in optical technology, structural design, and innovations of physics, to minimize the overall cost and the telescope’s overall size.
Put it where you can stop the light polluters from creeping up on it, because these suckers can last for hundreds of years, if built correctly. It could be designed so new technology can be installed without excessive, very expensive reconstruction.
I would guess that building a group of big mirrors would be cheaper than trying to make thousands of smaller segments all ground to the right shape. But that is just a guess. It's too bad the mirrors can't be made with that new 3D printing type technology. I saw a short video about that manufacturing technique on the website of the supersonic car they are building in the UK to try to get students interested in science and engineering. I laughed when I first read that it could revolutionize manufacturing. Now, I'm not so sure it won't. Then again, I would have bet that friction stir welding would never work. It seems like a totally impossible crazy idea, until you see it being done. Then it STILL seems impossible !
I would schedule the construction so that, should funding temporarily fall short, what is already built can be mothballed without it deteriorating much, until construction can resume. Design could be distributed worldwide over the Internet. It's not like you need security on a telescope.
They might want to consider political stability when deciding where to locate it too. You never know how alliances could shift in the future, as a certain large Asian country becomes the largest economy. Friendly countries today, might not be as friendly tomorrow. Just saying.