DiType Assistant
DiType Assistant is a GUI application written in Python (uses wxPython). Within the interface you may choose a file to format, select a stylesheet, add params for the transform, choose backend (PDF, PostScript, XEP), invoke formatting and observe the log.
It is is a clone of XEP Assistant, which you are likely to be familiar with, if you have ever used XEP (Java or Windows versions). What is currently missing in DiType Assistant is a configuration editor.
pending: rewrite from scratch, augment with screenshots and 'clickways'