Jem Es Fabulosa!/"Jem is Fabulous!"
I am not certain, but it appears that there was only one run of the dolls.  It still remains to be seen if there were fashions or playsets made.  Packages are in (Mexican) Spanish, and say Made in Mexico. They are made by a subsidiary of Hasbro, called "Juguetes Con Vida".  (translates to "Toys with Life" - thanks Omar!)  I got mine in the US, and all the other dolls I know of were bought in the UK, so I'm not sure who they were made for.  I've seen probably about 5 Mexican dolls in the UK for1 that was located in Mexico.  There is the theory that other markets outside the US were allowed to sell the (presumably cheaper) non-US dolls. 

They have many obvious differences, making them bona fide variations. 

To confuse this even more, enter the Spanish Jem dolls (as in, Made In Spain); which were apparently available in South America (I got mine from Chile).  So if you are from Mexico,  Central or South America, do check your doll closely to see what the country of origin is. Just because it was found in Mexico does not guarantee it is a Mexican made doll. 

A sample of some interesting differences:

  • The bodies are very distinguishable in that their torsos are extremely shiny and do NOT have any Hasbro/date/Manufacturer markings on them.  The faces are usually paler, and the skin tone of the arms and legs tend to be pinker and shinier than their US counterparts (this extends to Shana as well).
  • Mexican dolls can come with either stamped Hasbro heads, or non-stamped, presumably Mexican-made heads. 
  • The Mexican dolls are generally the first year dolls but incorporating some second year improvements (e.g.. Jem has star capped earrings, the guitars are a hybrid of the 1st and 2nd edition US guitars.)
  • The tapes included with the dolls were dubbed into Spanish!
  • In many cases the fabrics are different, so far all of the outfits originally made of lamé have been replaced with a thicker "pleather" type material.
  • The shoes are from different molds- click here to tell Mexican shoes apart.
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    DOLLS: I don't have all of the dolls yet, but here are a few examples I can share some pics and info about:

    Mexican Jem/Jerrica
    Mexican Roxy
    Mexican Shana
    Mexican Aja
    Mexican Pizzazz
    Mexican Kimber
    Mexican Stormer
    Mexican Rio (Can anyone tell me if they've ever seen a Mexican Rio? I've only ever heard he *wasn't* available in South & Central America/Mexico.)
    See also Britrock, for much more detailed information on Mexican Jem dolls.
    The Show:   Jem was aired with a Spanish overdub.  The songs however, were NOT translated.  (How odd that the dolls' tapes were). As the songs began, a guy with a deep voice said the title in Spanish as the song started in English.  Interestingly, a tape I got with my Spanish made Jem (as in, Valencia Spain, not Mexican made) also had a man with a deep voice introducing some songs (that were not dubbed) and narrating the story.   Apparently Jem was aired by the Mexican cartoon channel "Zaz" in 2001. 
    Other Jem Items:
    A series of Jem comics were released in Mexico.  They were smaller than the regular comics.  I've only seen one, "La Aventura de Joanna"  featuring Jerrica wearing a cowboy hat. In Spanish, VID Editorial, dated 1988.
    Show and Comic information courtesy of Charles.