By Carolyn Weber. Most jurisdictions around the country now have affordable housing requirements. The tricky part is blending entry-level designs into luxury communities without alarming the market-rate buyers. Some builders in Northern Virginia have found a solution that doesn't relegate the affordable housing to the perimeter of the project but instead places it next door to $800,000-plus, single-family homes. Centex Virginia and Edgemoore Homes are disguising affordable duplexes and townhouses with the "big house" concept. The architectural illusion masks the units, priced in the $120s, as one large, single-family home.