I’d like to second this request.
Magento already has the impressive layered navigation feature for finding products and flexible attribute creation, so the hard work’s already been done! I’d love to see a flex/ajax or similar interface put on top of this to show off these features to their maximum potential. Here are two examples of just how impressive this can be. Combined with Magento’s one-page checkout, this feature would make Magento a great user-experience.
And thanks again for Magento.