Ulm beefed up ...

[Saber Cherry]

Another possibility is an Ulm-only national spell, Earth Lore (or something like that) that is 2E and 8 Earth gems to cast, which reveals all level-1 sites in a (land) province, or a spell that reveals all elemental sites in a land province, like Tiamat's Something. Either would make sense for a race of earth-attuned miners. Although I like the special units better, because they seem fun=) But as you say none of this could be done through modding.