Hmm, all maps running FfH should have a minimum amount of mana, at least 1 per player, I think, due to the map checker. If you want more you can add more players. Or try terra map, you can usually get 3 or 4 more mana sources from the new world (you just might have to pry them from some cold dead orcs first).
Also, you might not know that some wonders give mana; all religious shrines, for example, and the soul forge. The wiki will fill in the gaps in my memory, stickied in the FfH 2 forum.