How do the words "Minecraft RTS" make you feel? If you answered "tingly in the pants," I've got great news. An two-man team out of Montreal, Canada by the name of Sauropod Studio is hard at work on Castle Story, a brilliant-looking mashup of Minecraft's gameplay with traditional RTS mechanics.
As you can see from the above developer walkthrough, much of Castle Story will feel familiar to Minecraft players. You'll still be mining voxels for resources, building up massive structures, and then defending them from waves of enemies, but in Castle Story you'll be doing it all from a god's eye view. Instead of running around and doing all the hard work yourself, you'll command an army of adorable little workers called Bricktrons, who you can issue commands to with an RTS-style interface.
Apart from the altered perspective, Castle Story offers a few more unique twists on the Minecraft formula. The first change is that gameplay takes place on a series of massive, floating islands, forcing you to be a bit more careful with your mining, lest you send a team of Bricktrons tumbling to their doom.
The second major addition is a physics engine that allows for fully modelled destruction. If you don't feel like watching the whole video, do yourself a favor and skip to the ten minute mark, when he blows up part of a finished castle. That, my friends, is impressive.
Castle Story is being developed on the Unity Engine, which means it'll support both PC and Mac at launch. Unfortunately, the project is still in the early stages of development, so it'll likely be quite some time before release. In the meantime, you can always try hopping on Ventrilo and shouting orders at the people on your Minecraft server.