I was thinking about the idea for some days, but I recently ditched my other idea (Startab) and decided to give this one a try. So, I spent ~2h figuring out how Chrome extensions work and finally decided that it's possible.
Then I wrote it to /r/SideProject/ and the next morning I saw 36 upvotes and 6 comments. I think I might finally have a good idea.
I still want to play with it a little, maybe create a PoC and make some screenshots, before putting up a landing page.