Question: Do you know any collaborative translation tool?

I've seen the suggestions in [this answer](https://webapps.stackexchange.com/questions/1108/is-there-any-social-translation-web-site), but I'm specifically searching for a tool to translate books (so large documents made of paragraphs, mostly), with possibility for other users to check/correct/validate other users' translations, roles (admins, validators...), and if possible something that has a nice API so I can convert the result into LaTeX to publish the book.

The tool could be SaaS (preferably free) or open-source (to be hosted on LAMP or similar).

Answer: 
<http://userscripts.org/scripts/show/97229>

> 
> This simple script currently just adds a few styles to show the available accounts on first click.
> 
> 
> 

Hope this helps.
Take a look at [this userscript](http://userscripts.org/scripts/show/16341)

It replaces the `Sign Out` link with a select list of accounts, so you you can instantly switch between accounts without logging out.