Is it possible at all to sync another persons private/persoanl contacts (not your own) to the Blackberry . So far Ive heard that its not.
We are on Exchange, BES, Blackberry device is 8700.

Sure! You have to do it over the wire though.

any advice on how?

Install desktop mgr on their PC, and configure the PIM sync to do a one way push to the handheld. This will allow you to add all of that person's contacts to the ones that are already on your handheld.

Hope this helps.