We do something sort of like that.
http://www.demolaystore.com/customer/product.php?productid=146&cat=35&page=1
It's basically a hack of the "detailed product images" feature. The alt text becomes the text of the link. For example: "Click to Zoom". The cool thing is that you can have more than one pic if you want. For example "Click to Zoom", "Click to see the Back", "Click to see the special detail that makes the product really cool."
I made a new template: "/skin1/modules/Detailed_Product_Images/product_images_links.tpl" Here's the code:
Then, I added the following code to "/skin1/customer/main/product.tpl" right below the thumbnail.
Code:
{if $active_modules.Detailed_Product_Images ne ""}{include file="modules/Detailed_Product_Images/product_images_links.tpl" }{/if}
Then, I deleted the following lines from the bottom of the same file.
Code:
{if $active_modules.Detailed_Product_Images ne ""}
{include file="modules/Detailed_Product_Images/product_images.tpl" }
{/if}