For what it’s worth, I use › with spaces before and after to separate items in compound titles. I found this to be much more readable than other approaches without taking too much space. Also, it is hardly ever used in any other context, so there is no ambiguity associated with it – if you use a forward slash as your separator, then you would not be able to use it as part of the title.
Topic A › Subtopic B › Problem C
In most operating systems it is not hard to assign the " single right-pointing angle quotation mark" to e.g. Ctrl+> or some other easily reachable key combination.
See also this related discussion.