Lout is a full-fledged document formatting system in the spirit of LaTeX, but lightweight (<<10 MB), with a very clean, publication-ready postscript -or embedded postscript- output. PDF and HTML output are available, but experimental, Gnu's ps2pdf on the .ps is to be preferred.
It supports everything you might want from a typesetting system (index, TOC, notes, bibliographic references, in- and-hyper-text links, imbedded graphics -raster formats or EPS-, near-perfect math equation rendering, native plotting and graphics, and much more; and, most importantly, it is fully tweakable with a text editor, as everything should be).
My current opkg package is not compatible with the Ben. Yet.
I'm thinking about porting it to the Ben (and by that I mean "I tried and failed at first but I might give it another try", of course). For more info about Lout itself see Lout's homepage