reStructuredText and Localization of Documents, Scaling to Lots of Content, Managed Over Time

I am wondering about tools and techniques to help manage translating and 
localizing documents. Particularly when scaled up and used over time.

Some considerations:

- Say a commercial service produces a translated rST document, how might 
we easily know that it is structurally the same (that the RST didn't 
accidentally get edited)?

- As documents change over time, sometimes there will only be small 
changes. We don't want to waste time and money redoing the entire 
document, but the translator should be able to see the whole document, 
to see the context, but only translate the changed part. (Alternatively, 
maybe in the only-one-change example, the translator needs to change in 
a different part of the document because of a change in terminology that 
should correspond.)

Some of the things I am wondering about slide into content management 
questions and don't have any language-specific aspects and are just 
worrying about managing rST documents over time, maybe with shared 
components that are used via include directives, etc.

I note that the Wikipedia has a page on content management systems, and 
another page on translation management systems. I'm wondering about rST 
considerations...

Thanks,

-kb