Espresso Libre theme for MacVim?
Solution 1:
If you have the TextMate theme file, you can use this online converter to spit out a (Mac)Vim theme file for you: http://coloration.sickill.net/
It should do a pretty good job of converting it for you, as it did for the ones I've tried.
Solution 2:
You'll probably be able to find something quite similar if not identical using vimcolorschemetest