Electric radiant heat??
 

Elec radiant heat, in floor or ceiling panel? I want an on demand zone heat source for my wife in her bathroom that will heat fairly quickly and can utilized just when she is showering. I think ceiling panel should warm her up faster shouldn't it?

Infrared heat lamp. Put it on a dimmer and it will last longer as well as let you fine tune the heat output.

A heat lamp would be by far the cheapest and easiest to install.
I did electric in floor heat in one of our bathrooms and the warm floor is great, an infloor thermostat gives better control.
The heated ceiling panels of course have the advantage of not being bright or oddly colored like a heat lamp.

So it really depends on what you want, what your budget is and how much you want to rip in to the bathroom.

I would start out with a heat lamp bulb in the ceiling.

I tried the heat lamp option. She didn't like how it heated very small area and she would use it for extra light instead of just warmth while toweling and at 800w it was the least efficient lighting ever.

These look interesting
http://www.warmlyyours.com/en-US/radiant-panel-heating

I tried to research them but I did not find that much info on them.

Invisable IR 120VAC 100W standard base.

Don't let her read labels on product or you will be sleeping in the bathroom, hehe

http://www.amazon.com/BYB®-ReptiCare...Emitter+Heater

http://www.amazon.com/Amico-Ceramic-...A1THAZDOWP300U

Cheapest way to get lots of fast radiant heat is 2 or three 250w IR heat lamps.
Thats what we have (3 of them) in the old bathroom I am redoing, only change I am going to make is to the heat lamps is putting them on a timer and give them on their own 15amp circuit.