I did a built in 8 ft buffet in our dining room that I love. It has 27" drawers on each end flanking a very wide (44") door-cabinet. Behind the cabinet doors, I have two deep ROTS (with heavy duty glides), I think it balances things nicely. There are "furniture feet" on either end, too, to pull things together. The drawers on each end hold linens, and the ROTS in the center hold TONS of serving pieces. (Are you doing anything up top? I did, and I like what I did . . . see images for details.) FWIW, I went with standard 24" depth and it allows for lots of storage space. I think 18" depth would be somewhat limiting, so I'd suggest going with 24" depth if you have space. The buffet is the part on the right of this image.

It's worth what someone will pay. It has no antique value because any part that was antique has been so modified as to be unrecognizable. The top is one thing. You don't show the whole thing but it might have been a stand alone piece or perhaps the top of a different sort of bottom. The bottom never had glass doors nor certainly the Chippendale pulls. I suspect that the drawer and the legs are from another piece entirely. It has use as a storage piece.....but it's very strange looking.

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.

Are there any clues on the back of the piece? Any stamping? What is the stamp on the inside of the top drawer, typically on the inside left side. Is there a locking mechanism on the 2nd drawer? What do the dovetails on the drawers look like? Its a very pretty piece!!