So I've finally got around to really start Tryton module dev to customize it to what we need.
I plan to put stuff that is useful as examples or maybe directly as-is on my github: https://github.com/LordVan/tryton-modules
On a side note this is trytond-4.8.4 running on python 3.5 at the moment.
The first module just (re-)adds the description filed to the sale lines in the sale module (entry). This by itself is vaguely useful for me but mostly was to figure out how this works. I have to say once figured out it is really easy - the hardest part was to get the XML right for someone who is not familiar with the structure. I'd like to thank the people who helped me on IRC ( #tryton@freenode )
The next step will be to add some custom fields to this and products.
To add this module you can follow the steps in the documentation: Tryton by exampleShare on Twitter Share on Facebook