MoM had a fairly effective method of dealing with resource protection. If you melded a magic node using a Guardian Spirit rather than the more basic and cheaper Magic Spirit, the node would effectively be guarded by an invisible unit that has become one with the node. As far as I know, there was no more upkeep for the spirit once it had melded.
I don't really know how resources are captured in Elemental, so I can't comment on how a similar feat might be achieved. But if anyone can think of something, it will be in this forum, which to me is a resource captured by the player Stardock. What is the upkeep I wonder?
*EDIT - How about a group of Pioneer Bravos? Rather than simply being consumed by the resource, they set up and man a perimeter defense that is difficult to take down early in the game, and that is also upgradable. Given that they are guarding a resource, that resource should be able to maintain them, or at least 80% of their upkeep once they have been 'consumed' or affixed to that resource. Someone else can come up with a better unit type name than 'Pioneer Bravos'.*
