Carver Gnarvester (Al and Ti) http://carverbikes.com/bikes/titanium-gnarvester/
RSD Big Chief http://www.rsdbikes.com/portfolio/v2-big-chief-cr-mo/
Muru Mungo (australian, but ships to US ) http://www.murucycles.com/mungo-plus
Travers RussTi (doesn’t ship to US, but nice frame and their Prong XC fork is one of few carbon boost forks) http://www.traversbikes.com/russti.html
I was looking at titanium for a while