Electric placemats

My fiancee suggested a project for me - make placemats that would keep plates warm throughout dinner, and therefore keep the meal palatable (she really doesn't like cold food).

I see two ways to do this - induction heating, and a ceramic thermal mass with heating. Leaving aside the issues common to both, ie how much power would be needed, how to control the temperature, and running power to them on the kitchen table (or whether batteries are even feasible), let's examine the options.

Induction heating

There are some fancy stoves that do this. From memory, it basically electromagnetically induces a current in a metal body with AC, which heats up from all the eddy currents. This requires pots and pans which are suitable for induction, but on the other hand, it can be more safe because you can put a plastic container or your hand on the stove and nothing gets hot, as long as it isn't already hot from heating something before.
However, there are some downsides. Few plates are made of metal, so you'd need special plates, or rather a plate and platemat set, for every person eating. Cutlery is also metal, so it would probably heat up too - you wouldn't want to leave your cutlery on the plate for a few minutes, then pick it up again burning hot! Finally, you have to run AC to your placemats, which means thinner cables than DC, but more dangerous current to have around drinks and knives.


Heated ceramic

I imagine a ceramic insulator/thermal mass around nichrome wire, or tungsten heating element such as used in electric frypans. The base would need to be a good thermal insulator, possibly wood, to stop it from burning the table, which might make it rather thick. You could use AC or DC power. You can use any plates that can stand being warmed.


Let's summarise:

Induction heating - pros:
Safer heating mechanism
Heats faster
Thinner cables
Thinner placemat?

Induction heating - cons:
Requires plate + placemat set
Cutlery is heated too
More dangerous AC

Heated ceramic - pros:
Can use any suitable plates
Choice of AC or DC (DC would have thicker cables, but is safer)


Heated ceramic - cons:
Probably thicker placemats due to insulation
Takes more time to cool off
Heavier?


I'm not sure which of these approaches would use more power, or be more costly to produce. Then there is heating control, but if I solve my electric frypan heating problem first, I can use that solution.

I'm going to ask Hackerspace Brisbane for their thoughts.