WP Coder - Sub Domain User Feature

Need the ability for an end user to be able to fill out a form on my website which will allow the user to enter their desired sub-domain, example ([login to view URL]) then they enter the website name and select from optional themes and hit submit and a child wordpress copy website will be create for them with all the features and functions already setup in the main [login to view URL] can then access that website from the sun-domain they created. The site will be listed in my admin section under accounts.