If you ever get to New Orleans, you will want to visit the Gallier House on Royal Street. This house was designed in 1857 by noted architect father-and son Galliers. The Galliers were quite wealthy, more so than the Reys would have been. Items in the Gallier house served as inspirations for creating the fictional Rey home, including Cécile's bed, Cochon's cage, her doll as illustrated, and the parlor.* In fact, in the Gallier parlor is this convertible Hedges or Metamorphic Desk which dates to 1854:
It was this desk that Cécile author Denise Lewis Patrick reportedly fell in love with and encouraged AG to produce for the collection. We're lucky that AG did so, as it's an incredibly distinctive piece of furniture and seems to intrigue even those not otherwise interested in Cécile and Marie-Grace.
Cécile is able to sit at the desk while wearing her crinoline, and the seat is deep enough that she does not slide off. The under side of the lip would have been leather when flipped over, but AG's version is wood and that's just fine.
No grade less than an A is possible. It's a great, quality piece.
ETA a few quick pictures showing the Parlor Desk with Rebecca's Settee. Strictly speaking, the settee isn't ornate enough for the era but the pieces sort of cry out to be paired together. While the woods don't match, they do complement one another and combine to create an elegant setting.
(Over-exposed settee, ugh, it's not really that pink).
* The house also supposedly served as inspiration for Lestat's townhouse in Anne Rice's novel Interview with the Vampire.