I recently purchased Maciej Kuciara's gumroad tutorial set, and this is the result of trying out some of his excellent techniques.
I used the block mesh included in the tutorial and then created my own image from that, using many of the techniques shown in the videos. I think it's safe to say that I learned a lot :)
I think there are 18 hours of video tutorials and a bunch of resources for just 60 bucks, I highly recommend picking it up.
So, big thanks to Maciej for putting those tutorials together, I can't wait to produce more images like this one!