Browser extension for Chrome, Firefox, IE and Safari (if possible)

Hi: I need browser extensions for Chrome + Firefox + IE (latest versions in all cases) + Safari (if possible). The extension needs to change the user's default homepage url and default search engine into one we provide, and once it detects that the user is navigating inside a certain URL (website) we provide, it needs to change a portion of html / css (for example: website's background color). The extension needs to comunicate with my website in order to: 1) My website will answer with some data (for example: the color) that the extension will apply. 2) My website may answer with a new version of the browser extension to update it. Also, I need a button on the browser linked to my website. I need the non-ofuscated source code delivered for each extension (in most cases is scripting anyway). If you already have developed an extension for any browser, please pm me with the url to check it. Thanks for your bids.