Back in the Warbirds Convention days, a few guys brought their Fresnel Lens setups, which were interesting to say the least.
There really was a good sense of depth and 3d effects, BUT:
1. You had to have your nose practically touching the screen, meaning you sort of had to hunch over.
2. You know those stereo-dot 3d posters that were all the rage a few years ago? You had to sort of de-focus your eyes and try to look off "in the distance" and then you would see the 3d image? Well, you sort of have to do the same thing with a fresnel lens for maximum effect.
3. Combining 1 and 2 could easily result in quite a heacache. Perhaps you could get used to it over time.
-Llama