I know -_- But it'd be cool!

Seriously though, Drupal provides a lot of stuff like HTML form generation and validation, easy to use AJAX tools, the authentication part, very good permissions handling.
However, I think that a lightweight version that relies on HTML + JS only would probably better to start with^^
(that is, by the way, why i would prefer JSON, which is much easier to use with JS, than XML is)
Will anyone make a draft as to how the interface should look like?