Hi,
I've published today my json2puml tool on Github (
https://github.com/jfudickar/json2puml).
Please include it in the other section of the
http://plantuml.com/running page.
I'm working on this for now nearly one year.
It allows to convert complex json files into nice PlantUml diagrams.
Have a look and enjoy.
I'm happy to get comments / questions / requests :-)
Regards
Jens