I agree, you really don't need any plans to make these. Here's an example of my own 'Mike Palmer's System' but made for the British National Hive, using reclaimed pallet wood. This is a 5-frame nuc system, rather than 4 - but using the same principles.
First make the sides - to the correct length and depth.
Then make the ends - to the required height, allowing for the rebate etc. - with the width being half the width of the 'parent' brood box, less the combined width of two sides. Butt the bits together with screw and glue - and that's it ...
Tip: If you don't have a table saw, I found it speeds up the process considerably if you make a cross-cut sledge for a hand-held circular saw, with a means of pre-setting length cuts. I'll post more details of this if you need ...
LJ