Melamine Rack Design

Hey, I was wondering if anyone has any plans or guidelines on building racks like those that they have at BHB. They had a snakebytes episode on their racks and how they have a company make the racks for them. They have a hole cut into the side of the melamine where the heat tape just slides in I think and I was wondering the easiest way to do that and how they wired the flexwatt together. I would think that if you wired the tape and just slid it into the side then the wires would still be hanging out the side and they wouldn't be able to keep their racks as close as they do. Anyone got any ideas? Post some links or designs please.

http://www.finegtps.com/rack_plans.php

he uses heat cable so obviously you would just have to make the cut just shallow enough for flexwatt and wide enough for it. and you don't need the special blade he talks about, tho it does speed things up, i use a table saw and just make 1/8inch (thickness of the blade) cuts to channel out stuff. takes a while but still works