Before we get into it, I want to point out that the creators of this idea recognized that what they're building is not a "true theremin" and have appropriately named the project.
Ok... with that little detail out of the way, meet Theophony - a "mighty interactive faux theremin" proposed by 15 artists collaborating to build installation art for this year's Burning Man festival.
The concept is simple - construct a giant optical theremin inside a canvas and wood Yurt. Cover the walls of the yurt with 4' x 8' murals depicting successes and failures in the pursuit of spirituality. Visitors enter the yurt, reflect on paintings, and try to play the giant theremin along with music piped into the tent, realizing that the pursuit of spirituality is hard.
I can think of no better place for this installation than Burning Man.
The fundraising goal is set at $8000, and with just 10 days to go at the time of writing, they've only raised a little over $2300. If you want to see this idea come to fruition, head on over to Kickstarter.com to make your pledge today.
Read: Theophony: The Mighty Interactive Faux Theremin(kickstarter.com)