Permanent Balloon Animals

[paco]

Maybe someone here can find an angle I can't...
I twist balloon animals professionally (I use 'animals' in a relative sense; I also make motorcycles, helicopters, machine guns, etc.) and I was wondering if anyone has an idea of how to make a balloon last forever.
I can make some very intricate creations, but the problem is that they slowly deflate over time, and then I'm stuck with a bunch of dead balloon animals. I want to figure out some way to keep the form indefinitely.
So far, the only thing I've tried is paper mache. This doesn't work too well, as you lose all the fine detail. I was thinking of something like shellac, but I don't know if it will dry quick enough or hold its shape over time.

Let me explain the physics of deflating balloon animals for the uninitiated.
After a balloon animal is made, the balloon is filled to relative capacity. But it won't hold its air permamently. After a few hours, they begin to decompose (they are made from natural latex, and as such, are biodegradeable). After a day or so, they have become slightly smaller, and after a couple of weeks (assuming no animals or kids get to them), they have retained their basic shape, but are about 1/2 their original size. At this point, they look like mummified balloon animals, and aren't as much fun to play with.

I love twisting balloons, but as an art form (or even as a craft), it's not really going to be appreciated until we find a way to make them last more than a few days.