"Profiles" for any Mac application? Is there a tool that lets me have a set of profiles, similar to Firefox, for any Mac application? So I can have two instances of an application, but each has its own settings...
Check out SwitchUp. 


http://www.irradiatedsoftware.com/switchup/


It used to be called rooSwitch and it was awesome for managing app prefs and data files. Now it's better and more awesome.