MuCommander

Use Vim as muCommander Editor
My approach uses the Vim server, to avoid constantly loading the executable. The  starts the server if it doesn't exist (without complaining about it) and loads the file in a tab.

Prerequisites

 * MacVim

Configuration
MacVim as editor: ~/Library/Preferences/muCommander/preferences.xml true mvim --remote-tab-silent $f

Prerequisites

 * GVim

Configuration
true gvim --remote-tab-silent $f