There are already quite a few Vim ports of the Cobalt theme from TextMate but I decided to make another anyway.
The initial work was done automatically using Coloration and then manually tweaked and added to.
This was done on top of a vanilla install of the Janus configuration of MacVim so whatever plugins are installed by default may have an affect on this.
There are a few limitations in the syntax files enabled by default so this includes a couple of matches and things that really shouldn't be in a colorscheme file but I've included them because I felt like it and it was the only way to really match some of the highlighting TextMate allows.
I haven't really touched the NerdTree colouring much as it's probably impossible to have different background colours in different panes. Can't guarantee that, though.