The opening of the 309-unit Paloma apartments at MainPlace in Santa Ana, California, in late October represents the beginning of a new trend that is expected to sweep across Orange County in the years to come. Many, if not the majority, of apartments to be constructed over the coming years will sprout from mall redevelopment. As exemplified by Centennial Real Estate at MainPlace, investors have laid plans to build over 12,000 housing units at 10 obsolete mall sites across the county.