Bob, you are right.
Steve House used Ti Pitons on his ascent of Nanga Parbat.
Re: Titanium Hardware: I think on of the issues (and you know more about the properties of Ti then I do) is that titanium is very hard. Thus it has less "bite" in the rock, wich especially for cams is necessary to help stop a fall. The metal needs to deform a little bit in order to create the friction necessary to get the camming motion started. Not anywhere near 100% sure on that one though, just my musings.
Where can one find a Carbon Fiber helmet?