>>>> I make use of a feature that in a project that consists of
>>>> several files allows me to compile each LaTeX file individually,
>>>> thus saving some compilation time while writing the
>>>> manuscript. I think such a system might be useful for inclusion
>>>> in LaTeX3.
>> It would be a nice feature, I think, and I have written some macros
>> to do that. Currently I'm working on a new class which will include
>> them.
> how different from the conditional stuff and the combined documents
> stuff that i mentioned?

Oops! I have put a link in my web pages to the faq you are maintaining,
and I didn't follow it... Let's cover it up...