Here is a schematic and board design that can be used to build a replica of ZFF's current sensing PWM. The board is designed using ExpressPCB, and is speced to use their double sided micro prototyping service. 2 PCBs fit to one board, with a set order size of 3 boards.
I've used 0805 sized surface mount components extensively to minimize overall size. The larger components will remain off board, so it will be up to the assembler to figure out how to add these components. The mosfet, opamp and voltage regulator is on board, and remains through hole form factors, with the mosfet footprint enlarged to a TO-247.