They just released "Gunsmoke - The Complete Series", which had 635 episodes, 402 of them were an hour long...it's a monster set...
143 discs, per Amazon. Ho Lee Shite.
Out of stock now. One buyer noted it was $335 to start; they were patient, and got it for $229. Not surprisingly, the packaging was cheap 'n' crappy. (I was warned about that when I got the full
M*A*S*H box set; slide the discs gently out of the cardboard sleeves to minimize scratching, place them in individual soft sleeves or jewel boxes, and never put them back in the original packaging again.)
I guess they wouldn't issue these things until/unless they had enough preorders. And there's always a small group of big fans for something. I bought Rupert Holmes' box set (yes, you read right) when it was originally issued in 2005 (I was hesitant because it was about $80, but my wife told me, "You are going to kick yourself for the rest of your life if you don't buy this, and I don't want to have to listen to you do that."). It's been out of stock since about 2006, and when it does pop up used on Amazon or eBay, it goes for four or five times that price.