Needed a heating pad for an experiment in my lab, and the quotes for custom made equipment were out of our budget. So I built one myself.

1) Select your controller and power supply. I used the following so STLs will work for these:

Temperature controller:
http://www.amazon.com/Digital-Display-Temperature-Controller-Great/dp/B002PIM3R8/ref=sr_1_1?ie=UTF8&qid=1374113319&sr=8-1&keywords=temperature+controller+PID

Power Supply:
http://www.amazon.com/Amico-Switching-Power-Supply-Adapter/dp/B008SNZD08/ref=sr_1_3?s=industrial&ie=UTF8&qid=1369688714&sr=1-3&keywords=24V+power+supply

Rear Power Socket:
http://www.amazon.com/Amico-IEC320-Module-Switch-Socket/dp/B0050HH70E/ref=sr_1_3?ie=UTF8&qid=1371500604&sr=8-3&keywords=IEC+320+socket

Plugs and transistor and voltage regulator were purchased from Radio Shack.

Feet were printed in polyurethane rubber, and resulted in a very nice solid and vibration resistant case.

Bottom, top and side panels were cut from 1/4 in plywood and screwed into the appropriate holes. Countersunk guide holes were used to improve appearance and finish.

Heating pad was constructed from Kapton Tape and cork board with a PT100 surface mount sensor from Digikey and a coil of NiChrome wire from Ultimachine:
https://ultimachine.com/content/31-awg-nichrome-wire-0