Valleman VMA203 LDC KeyPad Shield can be used with Propeller and ADC.
The 5 KeyPad buttons that are used on this module are connected via resistor network and the output is sent to the ADC via single Analog Data Line A0.
The Valleman documatation is rather poor but the wiring diagram can be found here:
This demo application uses two objects one as LCD driver and another to read the ADC
Which KeyPad button is pushed is shown on the LCD