Binary-types has been unmaintained for almost 10 years now. I needed to read binary files and have significantly updated the system in my fork. The original author says that he has stopped working on his repo and that someone else should maintain it.
@xach, I understand that you are one of the Sharplispers, and this seems like a good project to put under that umbrella. Are you able to move it there and update the Quicklisp link?