programmable capacitor

Hi, I am looking for a low cost programmable capacitor (2 - 10pF) this is about the range I am looking for cost is most important who knows ?.

Please no: MAXIM since I already know and its very expensive. Also Intersil I know already.. looking for other options.

Use a varicap diode controlled by a D/A converter. The D/A converter can be realized by an opamp and a bunch of resistors.

Is not an option, I need zero power !.