I watched this with my dad in the 70s and have fond memories about it. I haven't really rewatched the show since then, except for one episode 4-5 years ago, and I've been meaning to make a revisit for years and years. A couple of years back I found out the only available seasons were 1 & 2 so I decided to order a bootleg with all 7 seasons from iOffer. Fortunately, I did one more check to see if more had been released in the passing years.
And, lo and behold, the full series (kinda) is out on Danish dvd now. Denmark is actually the only place in the world where it's released in its entirety. In Australian they've released 5 seasons so far. Unfortunately, the Danish version only includes the edited version of season 1 (6 episodes were edited into 3) and the pilot uses the syndicated title ("Portrait of a Dead Girl") instead of the original title (WHO KILLED MISS USA). And furthermore, an episode is missing entirely from season 3 due to (Ricky Nielson) music rights. The Australian set of season 1 from Madman has the original 6 episodes plus the edited ones. And they include the missing episode in season 3 but sans the music. I have my info partly from an Amazon user in the States, WIKI and IMDb. The Danish season 7 also includes the telly movie THE RETURN OF SAM MCCLOUD (1989).
I've ordered the Danish set but will also get the Aussie set of at least season 1. Henrik Larsen has the Danish season 1 and he says that although they are in the original fullscreen ratio they look slightly squeezed from top down. Buy, hey, at least they're on official dvd now!
Scandinavians can get the Danish seasons from cdon.dk at 100 DKK a set.
Episode listing with original broadcast dates.