MacOS – Is it possible to install Linux packages on OS X

Although it isn't exactly what you asked for, one possible solution is to use the built-in ability to rapidly switch Input Sources (aka keyboard layouts). To make this function useable, you'll need to do a little setup.

Open System Preferences: Keyboard and select the Keyboard Pane. Check the option to Show Keyboard & Character Viewers in menu bar (1), then click on the Input Sources… button (2).

The Language and Text preference pane will open to the Input Sources tab. Select the input sources (3) you want to access on a regular basis. Fewer is better, remember you can always return to this tab and change your selections. When you've made your choices click on the Keyboard Shortcuts… button (4).

The Keyboard preferences pane will open to the Keyboard Shortcuts tab. Select Keyboard and Text Input from the column on the left (5). Then check the options to enable the keyboard shortcuts to navigate between input sources. (6).

If you stay with the default shortcuts, they will conflict with the default Spotlight shortcuts. Select Spotlight from the column on the left, and either deactivate or change the keyboard shortcut assigned to the Spotlight functions.

Now when you need to type a special character, use the hotkey to select the appropriate Input Source and use Lion's long hold function to bring up the choices for each character.

I am currently using Romanian as my Input Source . I know this because it's displayed in the Keyboard and Character Viewers menu item. A long press on a provides:

Once I've typed the Romanian character, I can use the keyboard shortcut to return to the U.S. input source.

I think that a package manager will do most of what you need. I will show macports as that is the one I know but the others have similar functionality.

If you use the standard packages ie the up to date ones that have been packaged then macports will do all the dependencies for you. e.g. building scipy knows it has to build numpy first and will do it. You can also ninstall a port easily - macports will tell you if any ports depend on it. If a port is chnaged then macports will update the ports depending on it.

You can also manually chnage the port to deal with development versions of numpy for example. You will have to produce a copy of the port file and edit that see macports guide. The minimum would be to change the version and the rules for downloading so you get different code but can include many patches for OSX specific functions.

You can keep track of what you have installed by port list (also more advanced calls to minimise the number of commands you need. The changes you made will be in your local Portfile repository which will need to be backed up and a small change to the defualt macports config made.