I'd completely forgotten that there was the Cadbury's Philadelphia. I used to spread it on a digestive biscuit for a bit of a treat.
I'm fairly sure I've (in recent times) seen Milka chocolate Philadelphia as well.
I'm a sucker for a chocolate cheesecake so have no aversion to the combination in that respect but I can't see it working with any stronger cheese.
Off topic but we got a 'cream tea' flavoured cheddar in a hamper once and absolutely everyone turned their nose up at it before trying it and then declared it 'quite nice to be fair' once they had. It was some sort of mildish cheddar with raisins and a sort of fruity strawberry compote woven through it. Somehow it did work.