While the famous Italian designer is keeping the rest of the details under wraps, the one-off supercar is believed to be based either on the 599 GTB Fiorano or the 599 GTO with some claiming it may feature a similar rotating central-piece roof to the 2005 Ferrari 575 Superamerica. The bespoke, open-top supercar will probably be powered by a stock 6.0-liter V12 engine, though it is difficult to say what other elements will be kept untouched, as we're talking about a vehicle built to customer specifications.

Pininfarina’s most recent coachbuilt 599 is the Ferrari P540 Superfast Aperta, made for another American customer, Edward Walson. Also, let's not forget the Ferrari SA Aperta, the convertible version of the 599 GTO. Even though the latter was built in a limited series of 80 units as Ferrari's tribute to Pininfarina, it is the closest thing yet to a unique convertible 599. That is, until the Ferrari Super America 45 makes its debut next month.

Other bespoke models confirmed for the 2011 edition of the Concorso d'Eleganza Villa d'Este, which runs from May 20 to 22, include the Audi Quattro Concept, Mercedes-Benz Concept Shooting Break, Infiniti Etherea Concept, Italdesign Giugiaro Go!, Rinspeed Bamboo, Renault DeZir and the Scuderia Cameron Glickenhaus P4/5 racer.

Until we receive some photos of the new Super America 45, take a look at the Ferrari 575 Super America, SA Aperta and P540 Superfast Aperta in our gallery below.