I wanted to work on this idea a bit more before posting about it here but I thought it would be best to open up a discussion and see what people think.
I had the idea of building a source control system which would allow users to vote on the merging of pull-requests. This would mean that the "official" hashed code tag would be stored somewhere on the blockchain and only be modifiable following a vote by the users. These votes could then be delegated by users to a core set of developers to allow them to work quickly, but could just as easily be revoked again during times of controversy.
I think this would tie-in quite nicely to having the actual code itself stored on IPFS/Swarm. since they also address content based on the cryptographic hash. The contract would then be able to point you to the correct revision in git (assuming git was used as the back-end) as well as the full source downloadable from IPFS/Swarm. Another way of looking at this would be that this would be making a git branch into a sidechain of the ethereum blockchain.
The biggest issue I'm seeing here is how to fairly distribute votes. One possibility would be to reward devs who successfully merge requests with extra votes. However this would mainly be rewarding contributors and would lead to the main devs having most of the votes anyway in the end. Another possibility would be to split the reward between someone who reports an issue and the person who fixes it. But this doesn't fully solve the issue and also leads to adding complexity to the system.
This last part is why I would like to see what other ideas people here have.