TempSensing.com has been providing cost-effective solutions for Temperature, Humidity & CO2 Sensing, Building Automation, Remote Monitoring, and other applications since 2005.
DS18B20 (3-wire) non-parasitic sensors
DataNab offers these 1-wire temperature sensors that use the DS18B20 chip wired in 3-wire mode. (3rd wire is dedicated power wire Vdd.)