Developers are plotting a nearly 93,000-square-foot indoor rainforest with free-flying birds, sloths, snakes and exotic plants — smack in the middle of Arizona’s scorching Sonoran Desert. Dubbed Paradise Earth, the four-story attraction is planned for 10.5 acres of Salt River Pima-Maricopa Indian Community land near Scottsdale and is being billed by its creators as the largest indoor rainforest in North America. The elaborate wildlife exhibit would also house freshwater fish, two-toed sloths, reptiles, amphibians and invertebrates, according to a conditional-use presentation submitted to tribal officials.