Simple WP Project: WPMU's ProSites plugin to be integrated with signup

I am creating a WP multisite network similar to [login to view URL] and I want the exact same signup page they have (preferably using gravity forms, same layout with edublogs, plus perhaps a little CSS tricks to match theme styling) to be created and integrated to WPMU's ProSites plugin. There is also a checkout page (again within the ProSites plugin) that needs to be integrated with [login to view URL] (NOT available through the Prosites plugin) merchant account when the user decides to go pro after a trial period. An alternative to Authorize is Stripe (available through the Prosites plugin again). I need TWO QUOTES for each option, one for [login to view URL] integration, one for stripe integration.