Here is the relevant documentation from the Mexican Customs website regarding computers:
http://www.aduanas.gob.mx/aduana_mex...139_10210.html
Which items may be included in my personal luggage exempt from duty?
Goods for personal use, such as clothing, footwear and personal toiletries and beauty products, as long as they are appropriate for the duration of the trip, including wedding party items.
Two photographic cameras or video recorders, 12 rolls of film or videocassettes; photographic material; two cellular telephones or radio phones; a portatil typewriter; an electronic calendar; a portable computer (laptop), notebook, omnibook or similar items; a copier or portable printer; a portable projector, and their accessories.
Two sports equipment, four rods, three speedboats with or without sails and their accessories, trophies or recognitions, provided that they can be transported normally and commonly by the passenger, one stair climber and bicycle
A portable radio for the recording or reproduction of sound or mixed tapes; or a digital sound reproducer or portable reproducer of compact discs and a portable reproducer of DVD’s, such as a pair of portable speakers, and their accessories.
Five laser disks, 10 DVD disks, 30 compact disks (CD) or magnetic tapes (audiocassettes), for the reproduction of sound and five storage devices or memory cards for any electronic equipments.
Books, magazines and printed documents.
Five toys, —included those that are collectible— and a video game console and videogames.
One device that permits measurement of arterial pressure and one for glucose, as well as medications of personal use; in the case of psychotropics the medical prescription should be shown.
One set of binoculars and a telescope.
Valises, trunks and suitcases necessary for the movement of goods.
Passengers over 18 years of age, may introduce a maximum of up to 20 packs of cigarettes, 25 cigars or 200 grams of tobacco and up to three liters of alcoholic beverages, and six liters of wine; in excess of the above, cannot be imported without complying with applicable regulations and restrictions.
Baby travel accesories, such as strollers and baby-walkers
Two musical instruments and its accessories.
A camping tent and camping equipment, as well as their accessories.
Handicapped or old travelers may introduce items for personal use, useful to have a better performance of their activities, such as walkers, wheelchairs, crutches and canes.
A set of tools including its case, it might have a hand drill, wire cutters, wrenches, dices, screwdrivers, current cables, among others.
Beddings, that will be able to include a set of matching sheets and pillowcases, a set of towels, a set of bath, a set of table linen and a set of kitchen.
Up to two dogs or cats, maybe introduced as well as their accesories, provided that the corresponding zoosanitary import certificate issued by (SAGARPA) is presented to the customs officials.
Última actualización: 14/abril/2008, 19:36, información vigente.
(emphasis mine)
An iPad would seem to fit under:
a portable computer (laptop), notebook, omnibook or similar items.