For cell phones these days you can buy a "charging pad" which basically lets you clip a small accessory onto your cell phone's charging (USB?) port and then you can just lay the combination down on the pad and the device wirelessly charges. an example would be Duracell's myGrid: Duracell | myGrid iPhone Starter Kit

Does anyone know of a similar product that is compatible with the iPad?

Last I checked those devices required you stick some big ugly knob on the back of whatever you want to charge. It was a deal killer for me at the time. If somehow technology changed and there is a charging pad that can charge things without adding that thing I might be interested, but until then I'll pass.

There is neat external charger out for the Ipad. It is the Mophie Juice Pack Powerstation.
Check it out to see if you would be interested.