There should DVD collections of lost pilots from the 50s- present. (1 Viewer)

[peggy]

There are two failed pilots that I would snap up in a heartbeat if I could find them.
Adam's House with Karen Valentine
The Ladies of Sweet Street with Doris Roberts
I am sure there are more but these come to mind.

 

[DeWilson]

It is likely any pilot shot by a major studio ON FILM most likely is still in their holding collecting dust - as for pilots shot on video tape, it could be hit or miss -forget tapes aging, but video wiped - such as with the American DAD'S ARMY pilot which only exists as it was recorded by one of the producers/writers on U-Matic.
As suggested, the best existing pilots for unsold series that aired are the anthologies - especially the MCA ones.