This sort of runs OT when it comes to Indiana Jones movie rip-offs, but hey, it's still some really interesting reading for Indy buffs and theme park freaks alike. Even better if you are both!
These two blogs do a great job covering the plans, concept art and why it was never built. Though that last part is an easy one... Money talks and Indy walks.
The Neverland Files: Indiana Jones and the Lost Expedition
JHM: Indiana Jones and the Lost Expedition... Found!