
Stanford Torus Exterior. Designed for up to 10,000 people in one gigantic torus 1.8 km in diameter that rotated once per minute.The giant mirror was meant to redirect sunlight into the interior. Painting by Donald E. Davis

Stanford Torus - a cutaway view showing the community section of the main torus.

Stanford Torus - Construction techniques. The chevrons being installed were designed to reflect sunlight into the interior while at the same time offering radiation protection.

Stanford Torus Interior - the torus had a cross section of 430 feet. Painting by Donald E. Davis

Bernal Sphere Exterior - The Bernal Sphere was Gerard O'Neill's alternative to the Stanford Torus. The main sphere was 500m in diameter and rotated at 1.9 rpm. The main sphere could house 10,000 people, with a series of toroidal rings at either end for agriculture.

Bernal Sphere - Construction of the exterior shell

Bernal Sphere - looking through one of two transparent sections directly into the interior of the sphere. The glass panels were designed to admit natural light into the interior.

Bernal Sphere - Interior view. Human powered flight in the lower g sections near the core was just one of the recreational activities envisioned. The central core also contained swimming pools for low-g diving.

Bernal Sphere - View of the agricultural sections, in multiple, stacked toroids, with cutaway to expose interior.

Photographed model of the Bernal Sphere

O'Neill Cylinders - Gerard O'Neill also came up with a larger space colony design that was basically a 32km (20 miles) long cylinder, 8km (5 miles) in diameter. Two counter-rotating cylinders would rotate in opposite directions in order to cancel out any gyroscopic effects and make it easier to keep the mirrors pointed toward the sun.

O'Neill cylinder - Interior View. Each cylinder was divided into six sections equally spaced around the long axis of the cylinder. Three sections were for habitation - the other three were gigantic glass panels that let in natural sunlight redirected from exterior mirrors.

O'Neill Cylinder - Interior view. The ends of the cylinders were capped with hemispherical 'endcaps' that could be landscaped into large hills and mountains. In this image, a large suspension bridge mimics the Golden Gate bridge.

O'Neill Cylinder - Interior View. The cylinders were large enough that they would produce their own clouds and weather.

O'Neill Cylinder - Exterior View. Each cylinder included a ring of smaller modules at one end that were meant for agriculture, research labs, and manufacturing.

Evolution of a space Habitat - The designs depicted were derived from this simple diagram -- the Curreri Space Habitat Evolution -- and presented the summer of 1977 at NASA's 'pace Settlements - A Design Study'
How much would one of these paintings be worth? And have any of them been stolen?
Emily,
Interesting questions, but frankly I have no idea.
Human-made space colonies are the way to go for human colonization off-earth. Such space colonies are not subject to the gravity of a planet or a moon. It will not be subject to the environment of a planet or moon that would make human life very difficult. Space colonies can be made to order. They can be easily accessed without having to deal with gravity or dust.