From the Barnstormers advert:
This is the only remaining Piper PA-40 Arapaho out of 3 built. Extensive mechanical restoration completed. (15 SMOH) Original paint and interior. It was rescued from Purdue University in 2018 and is in airworthy condition. Please review the Specs Page for the extensive amount of work that has been completed and other details before calling with any questions. Delivery available. We are taking offers now and will be showing it publicly for the first time at Oshkosh 2021. This is probably the only one of a kind Piper aircraft that is still flyable and airworthy.
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From the specs page:
1974 Piper PA-40 Arapaho
1270 Total Time Airframe/Engine
15 SMOH both engines and propellers in 2018
Lycoming (L)IO-320-B1A
Condition Inspection due August 2021
Original Engines Installed
Original Airframe and Engine Logbooks
History
The PA-40 Arapaho was designed to be the follow-on aircraft to the PA-39 Twin-Commanche.
The Arapaho differences include leading edge cuffs both inside and outside both nacelles which lower Vmc and stall speeds by approximately 10-15 kts., a single 60 gallon bladder in each wing, 6 inch taller main landing gear, a completely redesigned hydraulic landing gear operating system, strakes on both sides of the rear fuselage as well as above and below the rear fuselage, a redesigned windshield that extends further rearward at the top of the fuselage, redesigned dual pane side windows, as well as other minor changes.
The aircraft has similar cruise speeds to a PA-39 but much lower approach speeds as well as much better pitch authority in the flare which contributes to much nicer landing characteristics.
This aircraft is serial number 3 and is the last remaining Arapaho out of 3 built.
Interesting, thank you. Just been reading up on the Arapaho, which I’d never even heard of.
PA-40 Piper Arapaho
A say what????
Oh well, stated before, still learning, thanks for the education 
I think it would be fun to own. 
I assume it would retain some of the virtues of a Twin Comanche, including very maintainable engines. That would ease some of them practical burden of owning what is effectively a one-off.
