Bobu:
Thanks, hopefully this isn't a completely ridiculous post
You've missed something important...whatever device you connect to the center of the resistor divider will alter the resistances of the divider and therefore change the voltages. eg. If you connect something with a low resistance which goes to ground it will be like shorting out the lower resistor.
Resistor dividers are only really useful when the thing you connect to the middle has a very high resistance, ie. it can't draw any amps.