Hi HimSelf,
I fully understand your problem but (there's always a but...) it's not as easy as it seems to develop/design it correctly.
At some process of OSClass, we're required to know the "father" of a given category (Let's say you have "Father" category, and a sub category called "Child", let's add your "virtual" category and called it "Mother" )
If we ask now for the parent of Child, we should return Father & Mother, but,... what should we display in for example the breadcrumbs plugins? (It displays something like "Your site >> Father >> Child"), now,... should it Father instead of Mother? Or it's better to display Mother?
Even more, You will be able to make mother a child of Father
example :
Father >> Mother & Child,
Mother >> Child
Of course, everything is possible, but this is a bit complicated (if you want to make it flexible and useful for several users). We'll work on that, we want to make a great software.
My idea for tags, is that you will not have categories, only one. For example "yoursite", that category will be always hidden and instead you will use admin-defined tags. Again it's not the best solution and we're open to suggestions and help. If OSClass is not useful for you, it's not useful for us! So we want to work on it.
Thanks!