Dexter, didn't see the suggestion myself as it would have got my backing.
btw, your tag picture is a little on the large side...
Rich, so far as suggestions - I'd be happy with just one private members only area like the general forum.
I don't think we need a private version for all categories or even many categories - just sometimes something like the BBQ or security talk could do with being more private / non-published.
Although it would be good to confirm identity, my main concern is the public publishing / searchable web element making it too easy for drive by information gathering - targeted infiltration will always be a risk no matter how far you go with it and it has to remain the posters responsibility to keep this in mind in my view.