Check out my public .vimrc and my custom plugin script.
A little bit of info about this script:
each time that you save a file in vim, it automatically places it in $HOME/VIMBackups/ with some extra stuff on the end...
It creates a year month day directory, and inside that directory it places directory/ and then the directory and file of the file you just saved in vim.
So say you were working on ~/.vim/plugin/aplugin.vim, and then you saved it.
The script would create a new directory in Dropbox/VIMBackups/<year,month,day>/<full homedirectory>/.vim/plugin/aplugin.vim.(hour,minute,second).bak