Links are allowed pretty anywhere... but some considerations are needed: - if you have a different connection string, the model with that needs to be different for each app - cache, uploads, cron, databases, errors, sessions are tied to the instance (you can't show cached values of app1 to users of app2, nor uploaded files, cron script path may differ, databases is going to have different filenames because you have a different URI, errors and sessions are tied to the application and the users executing that only)
So, you're in the need of have the same files around for controllers/, views/ and static/. You could symlink all files into models except the one with the connection string. Either one of cp, rsync, symlink, python script, etc should suffice. --

