Create one page checkout for OSCommerce

We are using OSCommerce MS2.2 and are looking to replace the current four page checkout with a single page checkout process. We have designed the page layout (see attached) and are looking for someone to implement it for us. We do not want to use the one-page-checkout modules that exist for OSC, but want to create a custom one based on our layout. The page must have the ability to apply coupons, using our installed version of the GVCC contribution, via AJAX without leaving or refreshing the page. It should also have both Javascript and PHP field validation and integrated error handling for credit card errors.