Breadboard power supply

I've been having trouble getting by "big-ass" mosfet, from an old class D amplifier project I'd been working on, working with the 3.3V output from the teensy (gate charge, threshold voltage etc.).
Eventually I managed to put together a circuit with a 3.3V to 5V level-shifter + totem-pole-driver to drive the mosfet. This mosfet will not be used in the final design but I will use it for a proof-of-concept breadboard circuit .
According to my first simulations I am able to reach around 80% efficiency, which I find fantastic. It's not too close to the commercial ICs but hey, it's 80% efficiency with only a switch, inductor, diode and cap.

I've been thinking about the layout and I think I'm going to take a different route than I first planned. This will be the new layout for now, until I realise that there is something wrong with it.

After realising the big issue with getting god efficiency when designing your own SMPS I've been looking for controllers and converters to help me out. The result so far has been that there is none that is available to me and fits my needs so I'll have to turn down my current specs a bit, to say around 100mA for the two variable supplies, and do it myself.

I think I'll upload the .asc files from ltspice when I get a working circuit.

Info, code, schematics and so on will be published as soon as I have something to show =)