**UPDATE** For a general solution take a look at:
https://github.com/dirkwallenstein/vim-match-control

bad-whitespace - Highlights whitespace at the end of lines

Features
--------
There are configuration options that allow you to adjust filetype-specific
behavior of the highlighting.  You can turn the highlighting initially off, use an
alternative (e.g. faint) color, or suppress highlighting in the +/- columns of
patches in unified diff format.

Original Note
-------------

http://www.vim.org/scripts/script.php?script_id=3735

Author:  Bit Connor <[email protected]>
Version: 0.3

Get the latest version at:
https://github.com/bitc/vim-bad-whitespace

Inspired by the trailing-whitespace script:
http://www.vim.org/scripts/script.php?script_id=3201

Additional References:
http://vim.wikia.com/wiki/Highlight_unwanted_spaces
http://sartak.org/2011/03/end-of-line-whitespace-in-vim.html

About ~

This plugin highlights whitespace at the end of lines with a red color.

You can erase the bad whitespace with the command |EraseBadWhitespace|

You can manually toggle the highlighting for the current buffer with the
commands |ShowBadWhitespace| |HideBadWhitespace| |ToggleBadWhitespace|

This plugin is better than using the builtin vim 'list' command because it
doesn't show an annoying highlight while you are typing in insert mode at the
end of a line.

This plugin is better than competing plugins because it doesn't show
highlighting in buffers that are not modifiable, which is usually what you
want. This makes it compatible with UI buffers that happen to contain bad
whitespace, such as the quickfix window, or the fugitive plugin.

This plugin can optionally suppress highlighting in the +/- columns of a
patch in unified diff format.