As Leo gave the missing piece of information, to set a tab label by script (by raw-command), that Tab.SetLabel() is kind of less important I think.
Being able to set fontstyle or background color would still be nice.
As it fits this thread, I'd like to mention the "Tab-Labelizer" here again, imagining it incorporating Tab.SetBGColor() or Tab.SetFontstyle(), and it would be even more useful and wow!. o) Till then, you could maybe get away with setting up some kind of alias and adding special characters to be shown for special paths or foldernames with this add-in. Thinking of *#+ and whatelse catches your eyes, there could be some nice eyecatching characters in the unicode-land too to make use of.