Cooler lava lamp

I have a lava lamp, its neat, but lost its appeal after a few weeks, same color, always the same color. What if the lava lamp, instead of just a bulb, had a bulb, thermometer, and regulator, to keep a constant temperature. Ie. too hot, dim light, too cold, brighten light. Simple. Remember those little things that go through a series of colours when you warm them? Same principle just applied over a different temperature range, and well, the lava lamp.

There could be two kinds: normal, and flowing. Normal would just stay at a constant temp, and the "lava" would shift depending on how hot it is, red-blue going up, green-yellow going down. "Flow" would have a wider temp. range to change the lava's color, the temp regulator would slowly shift up and down, maybe every 10 min, and the lava would constantly change, slowy into another color, less variation, no boring same color. I could have a fireplace made out of one of these.