We are currently working on a shield that will do this all for you but don't expect it anytime soon.
Can be muxed (so can leds, switches, etc ) but for only five of them, why?It's more hardware, more code, more complications, longer development for the sake of what?
ATMELThe ADC converts an analog input voltage to a 10-bit digital value through successive approximation. The minimumvalue represents GND and the maximum value represents the voltage on the AREF pin minus 1 LSB.Optionally, AVCC or an internal 1.1V reference voltage may be connected to the AREF pin by writing to the REFSnbits in the ADMUX Register. The internal voltage reference may thus be decoupled by an external capacitor at theAREF pin to improve noise immunity.24.5.2 ADC Voltage ReferenceThe reference voltage for the ADC (VREF) indicates the conversion range for the ADC. Single ended channels thatexceed VREF will result in codes close to 0x3FF. VREF can be selected as either AVCC, internal 1.1V reference, orexternal AREF pin.AVCC is connected to the ADC through a passive switch. The internal 1.1V reference is generated from the internalbandgap reference (VBG) through an internal amplifier. In either case, the external AREF pin is directly connectedto the ADC, and the reference voltage can be made more immune to noise by connecting a capacitor between theAREF pin and ground. VREF can also be measured at the AREF pin with a high impedance voltmeter. Note thatVREF is a high impedance source, and only a capacitive load should be connected in a system.If the user has a fixed voltage source connected to the AREF pin, the user may not use the other reference voltageoptions in the application, as they will be shorted to the external voltage. If no external voltage is applied to theAREF pin, the user may switch between AVCC and 1.1V as reference selection. The first ADC conversion resultafter switching reference voltage source may be inaccurate, and the user is advised to discard this result.