On a second thought, it would surely be nice to have them in separate modules completely. This way, they could be "configured" the same way the current filesystem does (see [main.js](https://github.com/adobe/brackets/blob/master/src/main.js#L39)). Then it would be easy to replace it with a custom implementation. Having custom implementations might not be your immediate need, but it is mine (of Intel XDK). :)

If you don't have spare time for it, I could come up with a PR for it later (Sprint 37). It's my bother at the end of the day.