In order to route the power and thermistor wires to the control board I used an high speed cut-off saw to chop out a hole in the center of the stainless bed support plate.

This turned out to be pretty difficult as this stainless plate is 3mm thick. The heat caused it to warp slightly, but I was able to (with the careful application of force) flatten it out again.

Closeup (the bottom is not this nice looking):