Better timer

Ok, a couple of things about how you're driving the MOSFET (I'm not checking the timer, just how you're driving your MOSFET). Now you have said in your discription that a MOSFET in Power Switching applications must turn hard on and hard off and must spend little time transitioning between the two states, which is correct, but your implementation is not. In your circuit, the gate of the MOSFET is charged up through a 10Mohm resistor! That'll take forever to charge the gate up and will result in a very slow transition from off state to the on state. You don't see it in your simulation because of two reasons: lack of capacitance in EC MOSFET model and a large timebase. Check this http://everycircuit.com/circuit/4902587772698624 I have done two things: I have changed the timebase to 1ms/s and I have added input and reverse transfer capacitance to the model (I have left out output capacitance as it is not important here). Push the push button and see the transition (I have also increased the load for proper representation). The MOSFET transitions slowly and heats up in the process.

What you need is a good, low impedance MOSFET driver http://everycircuit.com/circuit/4901481290137600

Here http://everycircuit.com/circuit/5324336851058688 I've enhanced it for you

Thanks for the feedback. I did not want to use PNP BJT or Opamps. If you look up timers posted here you will see, that tey eigher use those components, or take a couple of seconds to turn fully off.