I stumbled across this game tonight on Steam while I was looking for whatever happened to Massive Assault. (Answer: as of 2007 it morphed into Massive Assault Network 2, after a 2006 single player expansion, and all the Massive Assault games are available on Steam).
Mayhem Intergalactic is just what the topic title says: Galcon with a twist. You have planets, you have ships. Each attacking ship destroys one defending ship. Each turn you can send one fleet from each planet you own. Each planet produces a number of ships each turn, and here's the twist: you can upgrade one planet each turn. Upgraded planets produce more ships per turn. It also has a rally feature, which is nice for staging ships near the "front lines".
It's also multiplayer, though I didn't get a chance to try the multiplayer with the demo.
It's a fairly simple game, but in a very appealing package. A lot of fun when you want a break from frenzied action games. Also it'd be a perfect iOS game, in fact it would surprise me if something like this wasn't already available for iPhone.
For some reason I'm balking at the $20 price tag. I may just wait for a steam sale. But it's a one-man production, and the developer is called "Inventive Dingo". That has to count for something, right?