I play that type of map pretty exclusively and see all of the resources represented.
I'm wondering what 'resource setting' you use of the map?
Logical, Irrational, or Crazy?
I'm not sure if that just affects the positioning of the resources (wheat in jungles, cows on ice, etc.) or the number of resources too.
I always play crazy resources, which provides more resources than the other 2 options I think. With crazy, you get a proliferation of 2 or 3 resources, and there`s a far greater chance of not having any of a certain resource, even on a huge map.
These would create temporary buildings that consume one resource and provide another (like how BtS Cooperations work). There would be several of these, allowing nearly any resource in the game.
Not sure I like the idea of being able to create any resource in the game. It`s the scarcity of resources and the strategic balance this creates that makes the game interesting.