Most bespoke/coachbuilt/limited run designs are based off an offering a manufacturer already builds and with that it will have some touch points shared and one can see the lineage. It's simply too cost prohibitive to get a bespoke chassis certified to then allow a truly bespoke body.

Bentley is on their third very limited run from Mulliner which included a speedster take on the GT, complete with no roof as well.

Like the Bacalar, the Midsummer will most likely be part of the owners collection.

Bentley Bacalar

Bentley Batur Coupe

Bentley Batur Convertible