Charles I'm sure word can handle 1000 pages. That is also not my question.
What I like is to have for every chapter a separate file and combine that to one report. If I make a report I can pick the chapters I need en write some new chapters. I can use the copy/past function. But that is really stupid to do this for 100+ page documents.
Why I like to have several files it that I like to have a file with only the introduction one file with the way I did the experiment etc this are mostly the same. Than I write the results for that test with conclusion and than I end with a standard text. I can make every document by using a standard report but if I chance something (in the introduction) I have to do this in all reports but if I have a file only with the introduction I just reposes the excision reports and automatic the update introduction textfile is used.

I you have worked with LaTeX (not latex) you know what I'm talking about.
Small section from a TEX file in LaTeX
[code]
\include{010-inleidingV1_0}
\include{020-storagesV1_0}
\include{030-materialsV1_2}
\include{040-conceptsV1_0}
\include{050-results20140204}
\include{999-conclusion20140204}
[\code]

Between { } are separate text files