RTS Thread? I have to mention PERIMETER: Emperor's Testament, a pretty obscure game from the Russian developer K-D Lab. It is an expansion to the game PERIMETER, but I have been unable to find it anywhere either legally, or illegally.
YouTube video.
The game doesn't even have a Wikipedia page, so here are some bits from the IGN review:
Your basic core building is the Frame. It's the city where your people live. You'll plop your Frame down on a flat piece of land and then send your brigadiers and builders out to level the land and construct new buildings. Land leveling is very important in this game as your nanotech can only extract energy from flat ground. Energy cores act as the hubs for energy collection and also serve to power nearby buildings. The cores are all linked to each other and your Frame forming a large network that powers your entire base.Basically, you build Energy Cores around your starting building, they send a beam of energy to it or a nearest Energy Core, that produce the only resource in the game which is unsuprisingly called Energy, and also suply power to your buildings, which can only be build near a Energy Core. At the start of a game you have some Builders which build your stuff, and Brigaders which you can use to terraform the land to your advantage, or to your enemy's dissadvantage.
There are only three buildings with produce units, which you then combine to create something else. Here is a part of the Gamespot review for the original game which describes it pretty well:
There are three basic kinds of robotic units in the game: soldiers, officers, and technicians. Individually, these units aren't very powerful, but if you have the technology and the appropriate numbers of each unit, you can meld them together and transform them into something much more powerful, like a mobile rocket launcher, tank, or aircraft. You can even turn them into burrowers that can tunnel beneath an enemy base, disrupting the smooth surface and causing damage to the buildings. This reduces the need to build a gigantic army consisting of a half-dozen unit types, as you can just build one group that can transform to any need.And lastly, the game features an energy shield which can be deployed to surround all of your buildings, or around few specific Engergy Cores and the nearest buildings. Nothing can get past it, and any enemy unit that touches it is instantly destoyed. The drawback is, that it drains a huge ammount of Energy(usually more then what you are generating) to keep on.