At the moment I'm looking at 8-channel multiplexers added to the scale amplifier card to enable seven additional sensors off the card. Most of them seem to use a 3-bit address (3 more wires from the controller). It would work.
For my more grandiose plans of peppering a hive or other instrumentation needs with temperature sensors, those compact little DS18B20's would be the hot ticket ... as I understand it no multiplexing would be needed. A list of addresses would be, and it might take some software tweaking to operate them, as Arduino usually uses 7 or 8-bit I2C addresses. (Just checked, yup, I'd downloaded the datasheet already.)
For a job like that I might fall back on the UEIDAQ thermocouple datalogger, which has the additional advantage of being able to measure to 1320C.