..thermo-chromatic paint...
Hi, these guys in UK do it. Should be someone in your locale, this is an education website for schools and colleges.
Thermo-chromatic pigments link (UK):
http://www.mindsetsonline.co.uk/product_info.php?products_id=568
They do lots of other nice stuff too, to do with science,tech, arts and craft. They even have an arduino called a faraduino.
Cheers
Edit: PS is that video really real ? Wow!