Slr.vim is a project mainly written in Vim Script, it's free.
Statusline/Ruler rotation
This is a mirror of http://www.vim.org/scripts/script.php?script_id=1501
This script simply rotates around a preconfigured set of statusline/ruler formats. Some times depending on the type of editing being done it is useful to have different status lines.
See the comments in the file to see how to setup the status lines. Two status lines are already provided. Can configure in the script or in the .vimrc file.