1W Push-Pull Power Amp Design
Here's my thoughts. You want a power amplifier to drive a speaker right? And you also want to take progressively more current from its power supply as the signal gets bigger. Why don't you use a regular 1W amplifer IC and design, on the side, a small circuit that rectifies the peak signal amplitude and uses this to drive a current source that takes the required current from the PSU.

What does this solve? Firstly you can get 1W IC amplifiers from lots of places and they are not complex to build or get working. Secondly, a peak signal capture circuit (given that you can drive it from the amplifier output) is just a diode, a capacitor and a resistor. Thirdly, a circuit that takes current from the supply based on a demand signal (the output from the diode, capacitor and resistor) is easy too; it's an op-amp, a power transistor on a heatsink and a 1W, 1 ohm resistor.