Due to the high usage of this guide and the lack of comfort in Gist's commenting area, I decided to make a blog post out of this which you can find here:
http://blog.frd.mn/install-os-x-10-10-yosemite-in-virtualbox/
https://www.youtube.com/watch?v=tafqhSUfKnY points to: https://drive.google.com/folderview?id=0B9oZd81xqtTOckJOT25uTzVfT3c&usp=sharing