As much as it would thrill me to see some of the places in Middle-earth in reality, I'm not sure what to think about the idea of a Middle-earth theme park. Maybe I'm just thinking too much of a Disneyland-type park with rollercoasters and such.
If it's really
just the models, I fear it wouldn't get enough interest to pay off, like Squatter said.
What I
could imagine is a Middle-earth section in one of those parks where they have models of all the tourist sights from all over the world. That would be a nice thing indeed, as they usually have very good models and modellers, and with a few ME-experts to tell them how the places
really looked (so that they not just copy the movie), why not?