I’m either a dinosaur, or a fossil. 
We are slowly turning our small building into a library. Originally, I THOUGHT most of our books were labeled with Dewey call numbers. Turns out, most aren’t labeled at all. So, I’m shelving them according to how our family uses, will use, or has used them in the past. I haven’t any plans for barcodes. We will use family style boxes to store cards until they are returned. I understand things that way, and the future members will be able to play by these rules if they want to have access to our lovely books.
I’m shelving science according to HOW science units, just because this works better in my brain. I trap titles and authors in my brain and sort them this way anyway.
History is being shelved according to the timeline for the main character/event. If a book stands out as absolutely biography, there is a biography section.
Picture books and fiction are shelved the way they’d be in Dewey libraries; first three letters of the author’s last name.
Poetry has it’s own section, as do art and music. I’m basically shelving the way I compartmentalize a CM planning chart in many respects. Our youngest daughter is helping me with this project. She will be able to help anyone who has a question about how to find a book.
The yahoogroup is very helpful. I highly recommend joining if you think a library is in your future.