I am working on getting these changes into Jamie's script as best I can. I hope Jamie gets well soon so he can check my work . Through experimentation I found out that for the macdeployqt command, -executable does seem to work well (at least it seemed to do something for kioslave) and we might want to do some more with that. the -extra plugins command did nothing really, except break the deployment step because it did not recognize it. I ended up just copying the plugins and that worked fine.
I am actually traveling again, in Sweden this week.
Don't forget that you are listed as a contributor on the github repo - make a branch (not a fork) for your changes, and check them in! when you have it where you want it submit a pull request, and I will do some diffs and perhaps comment on enhancement.