A year ago, business was booming for Touchstone Living Inc. The Nevada builder had a list of 639 qualified buyers who wanted homes in its development about 15 miles north of the Las Vegas Strip. Today, that list has shriveled to about 30. Many would-be buyers are unable to qualify for loans since mortgage rates have surged to 6.94%, their highest level since 2002 and more than double the rate of a year ago. …Mr. McCormick said his new company has less debt and fewer lenders than his former company did heading into the 2007-09 recession, and has grown more slowly and bought less land. “I’ve learned my lesson,” he said. Still, he said, “I’ve never seen it change this fast,” …”How rapidly things have deteriorated is pretty remarkable,” said Ivy Zelman of real-estate research and advisory firm Zelman & Associates.