Several years ago[1] I requested an option called 'splitvertical' that would cause all window splits to be vertical by default. Christian Brabandt made me a patch I use to this day even though it was never merged: https://github.com/chrisbra/vim-mq-patches/blob/master/verst....

It's still fairly straightforward to merge. Ping me if you need help (email in profile)

[1] http://thread.gmane.org/gmane.editors.vim.devel/28395/focus=... http://www.reddit.com/r/vim/comments/2irn8j/vertical_split_b...