Sounds like a good way to get the shell of a space ship into orbit, but does depend on the composition of the asteroid. I imagine having 50 to 100 meters of rock as a shield would work better than a couple of inches of glass when contending with the forces in outer space. While not fully indestructible it will at least provide some shock absorption to all the stuff floating around out there.

Wither or not such a plan would be cost effective and practical will require a lot of research and planning, but an idea worth considering.

Where's Bruce Willis?!