Renting theremins?

I am an artist/musician in New York City with an idea for a sound installation involving multiple theremins. I have been invited to participate in an exhibition that takes place this August (soon!). Ideally, I would like to build my own, but I am not an engineer and don't really have time or money to figure out how to do that at this point. For the exhibit, I need three theremins that are small and self-contained (there won't be room or power for external amplification). Obviously, better sound is better, but the nature of the project does not demand "top-of-the-line" equipment: all those things like tone quality, precise pitch control, and even volume control are not necessarily critical for this particular installation. Does anybody know where I might rent a theremin in the NYC area? Or, could anybody point me to a rudimentary design that I can build quickly and cheaply? Of course, if anybody is intrigued by the project and would be willing to loan me an instrument for three and a half weeks, I wouldn't refuse. Thanks in advance for your help!

My web site has a page about

Gee, I guess I was stupid and didn't pay attention to the thing that says "do not use html tags". Oh well. That URL, again, is:
http://theremin.tomfarrell.org/buyTheremin.html

Thanks for the post. I checked both instruments: the Jaycar model has an internal speaker, while the Enkelaar model doesn't. Given the state of the dollar, the Jaycar model now runs for about $65 USD including shipping. Arthur Harrison also sells a kit that has no internal speaker for $41 USD plus shipping (if interested, you can see his page at http://home.att.net/~theremin1/).

I am currently in the process of setting up a rental company in NYC for unusual electronic instruments, circuit-bent instruments and theremins. I currently have the following theremins available:
Moog Melodia Theremin
Big Briar Etherwave Theremin
Hiwatt Theremin
Theremanic Theremin
Don’t think any of these will fit your purpose, but email me @ guyettes@aol.com if you want to discuss. Would like to check out your installation---can you forward date/location? Also, if you do end up making your own and want to re-coup your cost after the show, I might be interested in purchasing them.