Maserati Quattroporte I.5, the 1972 Frua prototype for Karim Aga Khan

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I'm researching Frua-bodied Maseratis and came upon this one-off.  The Quattroporte I, which was also designed by Frua, stopped being produced in 1969.  The slow-selling Quattroporte II, which was based on the Citroen SM, did not appear until 1974.

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But in 1971, Karim Aga Khan, a very good customer of Maserati, wanted and ordered a four door sedan.  It was built on top of the Indy platform and had a 4.9 liter V8.

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The car now resides at the Riverside International Automotive Museum in Southern California, which I have never heard of before.  Judging by this video, it has a small but impressive collection.