Davide of Ardbir controller fame has kindly given me the details of the guy in China that he uses for his externally heated silicone pad heater for his single vessel that controls his mash and boil
See orange pad on this vid
http://youtu.be/OKcZ1iaukjA
The advantages for biab'ers are obvious, just not sure enough juice in these to overcome the thermal mass of a keg as it's much thicker than standard pots
Warning in advance they will not be cheap
This is only the preliminary stages and may amount to nothing but if you did want one what's you wish list?
Length
Width
Wattage (I'm guessing 3kw) they will be 220v
Any other questions we need to be asking vendor?
At $175 delivered this is dead
Damn that's shockingly expensive! Cheers for checking at least.