PlainDoc is a document production system based on plain text files. It tries to keep most of the document in human readable form with the intent that the PlainDoc source code itself will serve as the plain text version of the document.

Fig-1: Generation of pdf from sources (simplified)
PlainDoc system was developed by Sampo Kellomäki (sampo@iki.fi) from around 2002 onwards with the aim of solving document editing problems for writing:
IT specifications documents
Software product manuals and documentation
Scientific and research papers
Legal documents
Presentation slides
Some of the goals were
Document source is the plain text representation, no separate conversion needed
Documents are intuitive to write and understand
Getting a neophyte to a reasonable level of productivity and achievement should be easy. A college freshman should be able to use PlainDoc after 1 hour training, provided that all the tool chains have already been installed
It must be very difficult to fatally corrupt a document; fixing corruption should be as simple as editing the file
It must be possible to do diffs between versions of the document
Using cvs should be well supported (helps to avoid fatal loss of document)
Enable use of plain text productivity environments like emacs(1)
The PlainDoc system MUST be serious enough to produce most any type of document and thus end the need to use any other system
Typeset quality output in paper and web formats
PlainDoc has now (Sept, 2007) been around for more than five years and it has been successfully used to produce
Major IT specifications conforming to formatting rules (120 page range)
Research papers and thesis conforming to formatting rules (200 page range)
Product manuals (700 page range)
Legal documents and contracts conforming to formatting rules
PlainDoc acknowledges its LaTeX legacy and does not aim at WYSIWYG (except in plain text document production, of course :-) however we are not totally against visual formatting either. Thus many hooks for accessing the underlying document formatter's capabilities have been made available, such as
Direct entry of TeX code (allows setting margins, etc.)
Direct entry of DocBook code
Direct entry of HTML code
Support explicit line and page breaks
Support for raw image placement (i.e. NOT using floats)
These should allow you to get your job done without the system philosophy standing too much in the way, while for most part leveraging the automatic formatting of standard constructs.