Thanks.
To be honest, I'm also surprised that not many games do this. It might have something to do with difficulty of implementation - I'm not sure.
The only other game that I've seen that does this is Thanks Tanks (a really old flash game that I originally got the idea from). It was relatively simple and only one dimensional though, so when I saw the theme for this jam, I figured it would be a perfect opportunity to breathe new life into the concept.