I've eaten a lot of homemade tamales made by Mexican friends of mine, some of the most delicious things on earth.
I looked on some Mexican websites that sell "hojas de maĆz" (corn husks) and there is never mentioned any particular type.
Ears of corn obviously vary in size depending on their growing conditions, so I imagine maybe you just need a bit more "good stuff" in the soil and you
will get corn husks of sufficient size.
Another possibility is to wrap them in banana leaves which is the apparently the next most common wrapping in Mexico, central America,etc.
http://www.naturalhub.com/grow_fruit_type_banana_new_zealand.htm