I've been working on upgrading Vim visual mode support in SE. I think I've gotten it to the point where I can release it for feedback.
Features:
support for {,}, %, and most of the other Vim movement commands that don't work out of the box in SE 12's Vim emulation's visual mode.
Support for using < and > to indent/unindent in visual mode.
pressing : in visual mode causes the EX commands to automatically take on the range of visually selected text (note that it's a little annoying because you have to deselect the text that gets put in the command-line and then add the rest of your command after it. Is there an easy fix that doesn't involve hacking SE internals?)
I cannot guarantee that this file will not do bad things to you. It works in my environment, but it may have dependencies on other macros I've written that I don't realize.
I use this file with SE 12.0.1. I used a previous version in SE 11, so it _may_ work for you in SE 11.
Also, it will blow away any of you current visual mode key bindings to rebind various keys in visual mode to the right visual mode command.
Oh, and I bound C-U and C-F to page up and page down, whereas C-U is usually scroll-up, which I don't use myself. Feel free to change keybindings in the file.