Rvmprompt.vim is a project mainly written in Vim Script, it's free.
A simple interface for rvm-prompt command
This is a mirror of http://www.vim.org/scripts/script.php?script_id=3539
rvmprompt.vim is a plugin that provides a simple interface to thr rvm-prompt command. So, you can use that function in your statusline. It provides a configuration variable used to pass tokens to the rvm-prompt command-