Thanks @celerygirl for the inspiration pictures! It's so helpful to visualize elements in the room! One thing though - I'd put the buffet on the other wall, on the other long side of the table since there wouldn't be enough room behind the end of the table. Thanks @beverlyfladeziner for the link to the Atlanta house in Buckhead. Lovely!! The light fixtures are nice too and I especially like the first one! @Elizabeth Minish, we recently moved into a new home from a much smaller place so there are a few spaces that I am furnishing and decorating. The house was new construction, but we did not select the paint colors. I probably wouldn't have chosen Moth Wing for the dining room, although I don't dislike it. Other colors on the first floor are Accessible Beige in the great room/living room, Nonchalant White in the kitchen/family room (considering replacing with Sea Salt), Sedate Gray in the office, Comfort Gray in the 1st floor guest room, and Sagey in the powder room and other bathrooms (all Sherwin Williams). (I wish I knew how to make one of those floor plans that shows which color each room is painted!) I tend to like neutrals and darker wood for large furniture items and like blues and greens for accent colors. Despite the rising popularity of brass, I lean towards brushed nickel, silver, chrome, etc. I do like oil rubbed bronze and black for fixtures as well though.

I can see the option for a longer sideboard but if the shorter one were centered & had appropriate art above I don’t see why that wouldn’t work. A super long pice of furniture is great if there is one that makes your heart sing & it fits and you need the storage there ( & who doesn’t need more storage) , but then it’s less versatile, harder to move and usually much more $$, fewer options, so I think most people likely to buy cheapo item.

Keep in mind that most sideboards aren't going to be designed to have drawers that accommodate large serving pieces. I have a lot of china that will not fit a typical set of drawers, nor would it be safe - when you pull out a drawer you are pulling out all its contents, which, depending on the fragility of the contents, may not always be a good idea. If you are only envisioning storing things like tablecloths and non fragile items, then a nice antique chest of drawers could work as well as provide visual appeal. I would also keep in mind why people like kitchen drawers over cupboards is because modern kitchen cabinet drawers are designed to be user-friendly, with specially engineered pulls and hardware to make it easy to pull out and close heavy drawers crowded with food or dishes or pots and pans. Sideboards and dressers are not going to be engineered to provide that kind of ease of handling.

With the darker floor, you may want to warm up everything in the dining room. You might start by staining the chair legs a warmer color. Change the cool gray rug to one in warmer tones like your wall color. We can't see the sideboard/bar cart you referenced. It may be a matter of what you can get your hands on unless you're willing to shop second hand &/or paint said items.