I understand exactly what you need, i have strong knowledge of HTML/CSS, Magento, and also past experience with CSS sprites. I couldn't find suitable example of similar project, but i can assure you i know everything what's need to get this job done. Please feel free to ask me any question or send me more information about this project (current website url) by PM, thanks. Also please note, i'll need temporary FTP access to your website, also into Magento back-end if possible (to be able clear cache etc.).