I feel like hacking into Unity and spent a couple of minutes looking for development documentation, source code, components, the stack of aplications used, etc. It all seems to be buried in the results. Can't find anything related.
Can anyone point me a good direction?
The Getting Involved with Unity is where this documentation will all eventually be documented.
There is an architecture overview that should get you started. If you want to add new places for unity-places, you can find some documentation here.
Unity's project page https://edge.launchpad.net/unity is a good place to start. You can download source code (mostly Vala with some C as far as I remember) from https://code.edge.launchpad.net/unity - lp:unity is the main branch.
Unity is built upon the Mutter so you can also check http://git.gnome.org/browse/mutter for more code.