I think that would be a truely awesome idea! I would certainly be happy to contribute some container templates.
Would it make senese to have some sort of "variable subsitution" in the compose files?
I am thinking something like:
1) Another tab in plugin which lets you define variables and strings they resolve to (e.g. %PID is replaced by '1003'), a user would fill these out the way they want them.
2) You download a template, and the templates which follow some sort of OMV standard, would use the same set of standard variables.
3) When you run docker up, the file is preprocessed and the varibales are swapped with strings or an error is thrown if a variable is used but not defined.
The idea here is that it would save users havng to explcitly define things like the same shared volume full of movies refered to in many containers and hopefully make it easier for users to get basic conatiners up and working.