Glad to help
Not sure I understand your last question, here are two screenshot of how GURM looks like.
GURM uses tabs for all managers, so you can setup all your needed resources and click on ok. Afterwards all chosen resources are going to be installed.
So if you are using all managers, GURM has 6 tabs. If you deactivate some managers in the gurm.ini, e.g. the Script-Fu manager, it doesnt show up in GURM reducing the numbers of tabs you have.
If you wanted to know if its possible to use tabs while using a python plug-in instead of a Script-fu plug-in the answer would be no and yes. The standard GIMP python window is very similar to the script-fu window, in fact it cant do everything you can do with script-fu. But you can create your own GUI with python using PyGTK, thats what I am doing for GURM.
The screenshots are taken from version 0.7 which I am currently working at, so do not get confused the most updated version you could have is 0.6. In addition the screenshots are taken on a linux machine, if you are using windows GURM looks more grey