OK -- I found where I'd read it:
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8 November 2005: Indy to stay, and something new in place of the ABC Theatre?
It seems that the Indiana Jones Epic Stunt Spectacular is here to stay for a good while longer. Plans to replace this long running show with a major $100 million + Eride are rumored to have been canned for now. Attention now has moved to demolishing the ABC Theatre, and the Sounds Dangerous show, and installing a new ride through attraction in that location. The timeframe for this is said to be within the next 4 years.
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This was from the wdwmagic site -- but 4 years out is, of course, WAAAY too long a window to cause any commotion now (so, my apologies!).
And here's what the same source said about Midway mania:
7 June 2006: Midway Mania coming to the studio soundstages?
The last few months have seen a lot of speculation regarding a new attraction, called Midway Mania, to be placed in the studio's soundstages. The huge soundstage buildings, including the Who Wants to be a Millionaire attraction, are speculated to become home to a new interactive dark ride, featuring a computer generated 3D environment, and moving vehicles, allowing riders to shoot at the environment. In short, the project is being pitched as a Buzz Lightyear's Space Ranger Spin - "The next generation".
Storylines for the attraction have been previously talked about as focused around Mickey's Milestones, but more recently, this has swung towards being based around Pixar characters, and in particular, the Toy Story characters. Each show scene would be hosted by a particular character from the Toy Story movies, complete with their own mission brief for the scene.
The time frame being talked about is to have the attraction up and running within the next 4 years.