Easiest method to create pdf from template using command line (without pdflatex)?

I have seen PDF files generated by using Python and ReportLab. In the open source version you have to do some programming to get to the output, but there are several examples and this should be straightforward for someone who could handle TeX.

What I have not used but what seems even simpler is to use rst2pdf. The generating/editing the .rst markup format is much the same as using LaTeX.