Yes! I am a reviewer for PullRequest and since I've been doing reviews with them I've been involved in at least one major review where I was given the opportuni

Yes! I am a reviewer for PullRequest and since I've been doing reviews with them I've been involved in at least one major review where I was given the opportunity to review the entire codebase. From there I was asked to give comments, suggestions, design ideas, and general feedback on a number of different criteria. I'm just a reviewer and can only comment on what I've experienced. But I can say that what you're asking has definitely been done.