Russian special forces have had titanium helmets for more than a decade. I have heard no reports on how effective they are.
The Sfera or Sphere, officially STSh-81, are bullet resistant combat helmets of titanium and steel manufactured with protective GOST ratings of 1 and 2 respectively. They are worn by the Internal Troops of the Interior Ministry in the Soviet Union and its successor state Russia.
Apparently available on eghey.