Need guidance for creating no dependancies between two installs of Blender I want to have two copies of Blender on my machine that share no settings or preferences. One will be my development copy and the second on is the production version. I need them to be separate because I will be publishing my code to all the production systems and I need this process to be replicated locally for testing.

I'm asking this because I see that by default they are sharing '~/Library/Application Support/Blender/2.70/config'

They also share 
'~/Library/Application Support/Blender/2.70/scripts

This is problematic because I intend to put my addons here for the production installations. Then my dev install complains there are duplicate addons.

I'd like this to be easier, especially since it will have to be replicated every upgrade to Blender.
At least on Windows, it is enough to create an empty folder config in Blender\2.70\.

Blender binary path is for example:
...\Blender Foundation\Blender\blender.exe

and the version-specific folder is here:
...\Blender Foundation\Blender\2.70\

Add the config folder like this:
...\Blender Foundation\Blender\2.70\config\

Blender will note the local config folder on startup and prefer it over the user dir. If you save the startup file or user settings, startup.blend and userpref.blend will be created in your local config folder. Scripts located in the user dir won't be picked up.