I just had an idea, what if it would be possible to, for instance make the shard resource tile interactive. What if the shard resources were being defended by a group of elementals (for instance fire shards hold fire elemental packs). Before you could build a structure on top of them you would need to free the shard of its inhabitants so to speak. The fights would be rather hard and give a decent reward in the form of gold or resources maybe even a magical item also with features that a certain shard would allow it to have ...
The same could be done with gold mines that are guarded by a troup of trolls, after you defeat the trolls you are free to mine the gold mine... etc
Anyway I'm looking through the xml files, and all I can think of right now is making the shards or mines notable/quest locations and after defeat of the guardians despawning the notable location and spawning the corresponding shard beneath the notable/quest location.
Anybody that has any other ideas?