Where to find marketing case studies?

I've recently started an online marketing blog for businesses turning their efforts online, and wanted to find unique case studies on how businesses in different niches were able to achieve this. I've been browsing a lot of different types of blogs, but don't really know where to obtain case studies for content. I wanted to mimic something like the experiments section that appear on blogs such as these. Does anyone have any suggestions on where to find case studies? If you have any stories to share, that would be great as well, much appreciated!