From Newsday:

Working with East Norwich-based Ballymore Homes, one of the few modular builders on Long Island, the Hoyt family had a custom-built, 3,500-square-foot home designed, created in a factory and delivered to their lot within seven months in April 2005. The home cost them in the low- to mid-$500,000s. It would have cost 20 percent more if it had been traditionally constructed....

"Friends of ours who had houses built the standard way had to wait twice as long as we did."

The full article discusses modular construction and prefabs in more depth.