This simple Chrome Extension shows the top comment for a Reddit post when you hover over the comments link.
Download a local copy of the project.
cd ~
mkdir chrome-ext
cd chrome-ext
git clone git@github.com:hamstu/reddit-top-comment.git
Then in chrome browse to chrome://extensions/ and be sure to check Developer Mode in the top right corner. Then click Load unpacked extension... button and choose the ~/chrome-ext/reddit-top-comment/ext directory.
Feel free to fork and improve.
Do what you want!