I, too, am in need of something of this nature. Ideally, there would be a way to associate an image with a Page, and an additional parameter would be added to the wp_list_pages function.
That way, you could call the wp_list_pages function, and it would generate a series of thumbnail images, one for each page, and each one would be linked to the page it is associated with.
As I have recently written a similar plugin, I may attempt to write a simple plugin for this – check out https://beta.dragonfly-networks.com – I will post the plugin there when it’s done.
