Thanks for the suggestions, but I have tried all the sources you list, including a lot of time spent on Google, trying track down this one part. I actually bought the donor seats from FerrParts, and while Russ has been very willing to help me in any way he can, he has been unable to locate the handle. Further, Ferrari has apparently discontinued this part (Ferrari Part No. 63998500) and none of the other recyclers have anything to offer at present. Any help from anyone will be much appreciated.
1997 Ferrari F355 Berlinetta
1995 Ferrari F355 Spider
2006 Maserati Quattroporte Executive GT
2011 Jaguar XJL Portfolio