Toll Brothers Inc, which dominates the market for large, expensive houses known as McMansions, is shrinking its square footage as the worst housing market downturn since the Great Depression grinds on. Toll’s newer offerings in Las Vegas include some of the company’s smallest and cheapest single-family detached homes. “It’s no secret that Las Vegas leads the nation in foreclosures,” said Nevada division head Gary Mayo. “The dramatic decrease in home prices dictates where we need to go with pricing and product.” The impact of a federal homebuyer tax credit and stabilizing unemployment numbers has fueled talk of a housing recovery, but uncertainty lingers. Sales of both new and existing homes fell in February. In Las Vegas, Toll has responded by including stucco, tile-roof houses measuring 1,673 square feet and costing in the low-$200,000s in a community called Traccia. That is less than half the average size and price of Toll’s single-family, detached homes.