I've given your plugin a spin and I'd really like to use it, for two reasons:
1. It's the only zoom plugin that has this stylish lens effect.
2. It's the only zoom plugin that doesn't output any warnings or errors in debug.log (and that means a lot to me, lol).
My only problem is that I can't make it work on product variations. The lens keep showing the parent image, not the variation. While I do have some coding knowledge in php, css and jquery, I'm absolutely parallel with Prototype.
In case you want to take a closer look at the problem, here's a test product page, with different images on variations: http://pastel.websiter.ro/shopping/concealer/cover-stick/