Creating Web Installer for CI Based Application

Im looking for a way to create a decent installer for an open source application, based on CI. Does anyone have any recommendations?

I was thinking have it so when they git clone/untar/unzip/whatever the files initially, and go to the folder in the browser, it would show
them a web interface that they can use to configure the app, something along the lines of...

1. Check proper PHP version and PHP dependencies
   
2. Check the proper file/folder permissions
   
3. Check other system related stuff (EG: Resources)
   
4. Have them specify the database creds, test them, and update the database.php file (If perms allow)
   
5. Create the first administrative user
   
6. etc
   

My question is, where should the PHP code for all this go? I was thinking maybe have the setup code in its own folder, then once the setup is 100% complete, just have the whole setup folder deleted... Ive seen that before, I actually thought it was pretty neat. lol