Median prices - warren/mar/link

paired houses - ofheo/case-schiller

hybrid - zillow?

http://www.zillow.com/reports/RealEstateMarketChartsAndMaps.htm?msa=United%20States

 http://www.zillow.com/reports/RealEstateMarketReports.htm?s_cid=emm-2007111BuzzQ3ReportRePro-bab

http://www.zillow.com/wikipages/Reasons-Why-Median-Sale-Price-is-Flawed?s_cid=emm-2007111BuzzQ3ReportRePro-medianprice