Here are some more pics.

You have some good inspiration pics. I think it would look fine if it were painted. I think a stained wood one could be over kill on the fireplace wall. Congrats on new found storage!

Thanks, Kendrah! I would paint it very neutral to blend in with the wall. Thanks for commenting.

Sounds like a great idea!! I think the doorway to the right of the fireplace kind of balances it, I think it’s a great find!!

Will you be able to get swinging bookcases that match?

Otherwise, perhaps just stained louver doors.

Thanks for the pics! What do you think about doing it with painted book case - similar to color of wall so it kind of blends in. I have a pic in my earlier comment.

I love it, esp if you need bookcase storage

I think painted could work...

Yes, painted the same color as your wall would be great.

@Lyn Nielson Your hidden room is fantastic! Love it.

I love this idea of a hidden storage. What a wonderful solution to create a beautiful space.

Thanks, folks! You really help me!

Have you said what your budget is? The pivoting bookcase doors might get pretty expensive. If you budget is on the small size you might just consider walling in the space and having a door.

Haha! I just read your comments to my husband (who doesn’t like change). He wants me to post a go fund me page!

How fun! I love the idea of hidden space.

This is an inspiring project. You have a Lot of space, now wasted, that can be turned into functional storage - yippee, fun!

I love your hidden door idea. How many houses have that!?! It's not so much about having something unique, it's about utilizing space for aesthetics and functionality. Designing that large space for storage should be done with care, literally determining ahead of time exactly what you intend to put there. When I design storage, I do so in terms of every square inch. In other words, just because you'd be making a new place to put things, and it will be hidden, don't design wasted space - make the space wholly useful.

You didn't say what the space measures, but it looks large enuf for a half bath. Just making that point to ask if there is another possible utilitarian use of the space accessed from the backside that may suit you? (asking...just in case, and Not suggesting a half bath is put there with access from the living room side.)

Either way, more power to you, always good to improve a home's function and aesthetic.

I understand the hidden or idea but why a bookcase at all. A hidden door a nice pice of art hung on it and done I would never do a 1/2 bath off an entertaining space .

Two thoughts, since the need for storage is outweighing all other considerations:

(1) you don't have painted woodwork other than the baseboard molding, and IMHO painted woodwork (doors and trim and visible shelving) will compete with the stained shelving on either side of the fireplace and create visual confusion. Even if they are the same color as the wall, the finish (usually semi-gloss) will reflect differently from that of the wall (usually eggshell or pearl). If you are going for open shelving I would repeat the style and stain of the shelves you have; if not, I would still repeat the style in the doors and stain them, for a more cohesive and intentional look.

(2) don't rip out the plumbing. Leave it in case the next owner wants to restore the bar feature.

Getting rid of a bar and adding a closet is a great idea. They are learning more and more about the dangers of alcohol and what it does to a brain and a body so a bar is not needed in a home. A closet is much more necessary in a house. Anyway you do it will be OK. Add a door or just make the little room full of shelves and drawers and doors.

Love mirrored or glass French doors, easy to install and goes with traditional home styles.

If the bookcase idea is too expensive you can also consider mirrored french doors as suggested by @Margo L.

The mirrored French doors is a really great idea. Never would have thought of that. Thank you!