You're right I remeber there being plans for The Great Muppet Movie Ride, and even the Muppets own Theme park called Muppetland! They cancelled all the ideas and propositions because of money issues.
Muppetland? OMG the rich villains!
How could they NOT build it?
I'll try to picture what it might be like if it was made....
Muppet walkarounds. (Mahna Mahna and Snowths would be cool)
And I'll suggest other ideas such as Lew Zealand's (outdoor) Boomerang Fish a thon.
Kermit's Swamp Place: an (indoor) area that's fun for all the family (along with everything else) that features Kermit's Banjo (maybe) in a glass case, a water fountain with lily pads, an interactive (talking) animatronic Kermit The Frog sitting in a corner and another intereactive part of somesort with a puppet Kermit, performed by an expert Kermit that's specially hired.
The Muppet Ride (obvious)
Maybe if funding and artifacts can be found there will be a medium (ever growing) sized muppet museum.
Also maybe a stage show (puppet show style).
And in the style of the great movie ride there cold be the muppet one but you don't go through any movies! Oh no you go thorugh Muppet Movies, YAAAAY!
There could maybe be a cart for it and in the barricaded front row of the cart it features some of the main muppets: Gonzo, Fozzie, Kermit and Piggy. And they comment as they go along and you drive through the best scenes. All recreated with stunning animatronic robots! Start maybe at a recreation of kermit's swamp and end with Kermit and Piggy's wedding. And it has all the best bits in between, maybe even scenes from the newer movies too (maybe). I love creating ideas!