Mad About You is a Sony show and not Fox. Currently Shout Factory has the distribution rights to Mad About You and after the low sales on season 5 they have stated more than once that the final seasons will not be coming out anytime soon if ever. As for Rhoda season 5, that is also Shout Factory. I think their negotiations with Fox fell through and they are unable to secure licensing for the final season of Rhoda.
James, that is wonderful news! Please keep us all updated and posted as to when we can expect these last two seasons to come out and hoping you guys can work on getting Season 5 of Rhoda out and Mad About You S6 & S7. Appreciate the news.
Muppet Show is Disney and not Fox. Again, James nor Fox have anything to do with The Muppets. I've been to Muppet Central the official Muppet site and there is no news on Season 4. More than likely music clearances are keeping this from happening. Or George Lucas is playing hard ball about the episode with the Star Wars characters in it. It's obvious that something really big is keeping this from being released or it would have been released by now.
I'm just hoping it gets released soon as they made these announcements a year or so ago and we're still wondering what's up here? Same applies to The Muppet Show S4 too.