My version of Andy's slider. R1 and R2 put the gate at about 9% of Vcc which will turn the MOSFET on as the MOSFET conducts R6 develops a feedback which balances the circuit. With 1mv in I get just under 500mv out. (notice while the waveform is not very distorted the negative peak is larger.
Increasing the input to 10mv overdrives the amp. Increasing the source resistor will tame the beast.
If you use a pot for the source resistor you can adjust the gain. Just something to look at.
The spice model - 2SK669 Amp
A zipped model in case the other link failed you. 2SK669 Amp Zipped