new syntax: SET variable = value FOR account

It would be great if we could have this syntax:

SET variable = value FOR account

The variable should be set immediately when specified user connects.

This would allow us to configure an application's settings without affecting the global behavior. This is useful for closed source applications, and for applications we'd prefer not to touch (for example because we want to be able to upgrade the open source application with a trivial apt-get, or because the maintainer of the application is unreliable).

Of course we'd also need a way to configure this in my.cnf, and a syntax to ask the server the default variables for a given user.

I hope this is possible.