The Ammonio PHP framework
Ammonio is a PHP web framework developed by Luca Cervasio. Its development begun to cover the needs of a webapp written to be multi account. I was also in need to manage parameters per account and per user. It implements the whole server side stack and some client side API to provide full functionality and fast get-the-job-done approach. As you understand this isn't a general purpose framework. For this task there are several out there in the net for any language. Ammonio follows the "code by convention" paradigm, top-down approach. See Ammonio features.
Download Ammonio sources from http://ammonio.org/download. Uncompress it and start writing your first application. See documentation available here and the get started page where you can find a working sandbox demo application.
Ammonio is open source. Feel free to fork it on GitHub and contribute to the project as you wish.