Expedition third row seats, I think around 2004 version. I had the front buckets, too, but they sat too high for me - sold them.
Father-in-law welded up a frame for the rear seats. Not movable forward/backward and don't fold flat. I'm sure you could fab (or have someone do it) a different mounting system. Mine has open space underneath for 'crap'. Not too bad as far as comfort goes. Fit between the wheel wells nice.