thx, sounds good. just ordered my first arduino board 
and i guess i'll just try the 8 x 4051 setup. the only problem i see are the pads/buttons. when i hook up a button that should be recognized as 'on' as long as i press it there will be the risk that i press the button while arduino is reading all the other channels and release it before the channel of the button is read. in this case the button won't be recognized, right?
so would the adc/spi version be a better choice?
@MokMo: Which sliders did you use?
so many questions :