For sale on Lexington KY craigslist. Priced too high but I cannot recall the last time I ran across a Matador wagon for sale. http://lexington.craigslist.org/cto/3046942565.html
Thought about this a bit, and I have a theory........ AMC, was a Wisconsin company in the 70's before Mopar took it over. My guess is that in the 60's and early to mid 70's they got a big percentage of their total sales in the upper midwest and east, and less in the western states and southwest. Becasue a greater percentage of their cars were in the rust belt states, a greater percentage of them fell victim to rust, as opposed to other makes.
To be honest, if the car is, in fact, rust free, and is in as good a shape as the seller claims, 5500 probably isn't bad. Like you noted, ya don't see them around very often. Cool find.
I actually think 5500 is reasonable for that given how many are around these days and how complete and nice that one is. I'd buy it. I would worry about that giant, and by giant I mean the size of my head, bubble on the passenger rear pillar. I wouldn't so much worry that it's rust, I would worry that it's like a hornet's next and if I stab it with a screwdriver I'll die.
Funny story for ya. My annoying buddy from high school drove one of these. It was red and his parents old car that he got to drive once he got his license. The funny part, or misfortunate, is that his last name was Wykoff. Everyone instead always called him Wackoff. It's pretty tough getting a date when the whole school knows you as wackoff. So, I'll forever associate these Matador wagons with Chris Wack, err, I mean Wykoff.
That right rear "D"-pillar blem is a dent, not rust. It'd be a PITA to fix, but not impossible, by any means. Cool wagon.