You could build a wall of bookcases, but they have no backs on them, you can utilize from both sides, put ornaments, neat office storage boxes or the like, you could even add a bench seat as a reading nook on the outside face of the bookcase, you could do it in which ever style you intend to adopt, modern?, with natural textures, classic with lots of cushions or retro with bright colours. This will seperate the office from the rest of the space but also allow air flow and light into the space and will not altogether cut you off from whatever else is going on in the house. I chosen a few example pics for you.

How about Shale Grey? Too light? Too dark? You need to pick a starting point and then go darker or lighter.

if you check the websites for some of the big building companies in your area you will find hundreds of floor plans...Google Project home builders and you should be able to find plans but also addresses of houses that you can visit to help choose which one you like best

I'm in WA, so this is what happens here. Find a builder and a design that you like. In WA a lot of companies do a Demolish and Build all in the one contract. If you are not organised this maybe the way to go. Speak to the builder and get all your design issues sorted, and what the time lines are for the build to start. Contact a demolition company/s, that is appropriate for your type of home removal. Questions of correct asbestos removal, or what is salvageable for resale, are good to ask. In WA, homes need to be baited for 4 weeks prior to the actual demolition. So while your arranging your new home design, this can be commenced with demolition company. The demo company also has to apply for and be approved a demo permit, before any of this starts to happen. If you are living in your home, then you need to find other accommodation as soon as you have organised the demolition people. Approval is done for demo, home is baited and sits for 4 weeks, home is demolished. While this has been happening you have organised your design and building approval etc etc. The builder will take over the site, once you have had the demolition completed and signed off by council. We started the process with our builder for design in July 2013 We signed contract in Feb 2014 We had our home physically demolished in Feb 2014 But started that process 6 weeks prior. Building licence approved in June 2014 Moved into our new home June 2015. Double storey, double brick, concrete slabs upper and lower.