I believe every Techstars batch does a tools survey across batch companies (at least R/GA Techstars in NYC did) then emails everyone the summary with bar charts.

The one I have is mostly about analytics, sales, and support tools, and unfortunately repository hosting wasn't a question asked. I also wish they would make this data source public so others could see shifts early -- for example the wave from HipChat to Slack would have been very visible.

Perhaps StackShare might be the closest open source of similar data.

http://stackshare.io/code-collaboration-version-control