It's great that we got a clip, but I'm wondering why they only gave us a small bit of the beginning. Seems all the action took place after the introduction... a cute and entertaining introduction, and I'm sure Jim ad libbed a couple lines... but I'm with you. I wish they had a clip further into the show. Unless some kooky copyright thing with Disney kept the rest of it from being shown. If that's the case, I totally understand.
I for one am surprised that Disney didn't get the rights to that (unless perhaps it's public domain). I'd read that Disney got the rigths to Tale of the Tinkerdee, so it would make sense for Disney to get Land of Tinkerdee. The only Muppets in that special are Rufus and King Goshposh, who were heavily featured in productions that Disney does own the rights to, so I'd assume Disney owns those characters (unless they just aren't trademarked anymore, since they haven't been used in years, or unless the two companies don't really care about ownership of such obscure characters).
Aside from that and the Wheels, Crowns, and Flutes commercial (featuring Beautiful Day Monster) it seems The Jim Henson Company has been avoiding clips it owns with Disney's Muppets. Or maybe it's just a main character thing (though Henson did upload a film, I think Limbo, which briefly featured an image of the original Kermit puppet). I don't know if Henson needs permission to upload clips with other companies characters or music, but it would make sense for Henson to avoid the clips with Muppets or Sesame Street characters to avoid confusion (the company has uploaded a few things with the Cookie Monster prototype).