Can I make a symlink (to a .app folder) in Applications directory show up in spotlight?
In the Finder, press CommandShiftG for Go to the Folder. Type /usr/local/Cellar/macvim/7.3-61/ and press return. Select the file (actually a folder) MacVim.app Press CommandL for Make Alias. Depending on permissions, you may be prompted for an administrator password here.

Press CommandN to create a New Finder Window.
Press CommandShiftA to go to the Applications folder in that window.

Drag the newly created alias from the window in which it was created to the window containing the Applications folder. Rename the alias so it no longer ends in " alias".