I took the advice offered here and changed my libraries into custom column metadata using the existing tutorial 'Managing subgroups of books, for example genre' as my playbook. I then went ahead and used the view restrictions to create some views, and I used the View Manager plugin to create a default view which only shows books I am currently reading: Genre = Current.
What I really, really like about this suggested approach is that it is actually an improvement over my organization of printed books. What using a custom column with tags allows me to do is include a book in several collections without duplicating the book! Its simply awesome! For instance, a new book can be both current AND whatever category it will be when I finish reading it, I simply will change the metadata Genre tag to remove Current and I am good to go!
I want to thank everyone that contributed answers to my conundrum, I think I used all the suggestions in the end!