The lightest MTB frame in the world is called RossoCorsa, has got a monolithic construction and is fully Made in Italy by SG Compositi company (owner of GrigioCarbonio brand).
With only 49 grams (70 mm lenght), GrigioCarbonio Attack is the lightest bicycle stem in the world and one of the strongest and most beautiful ones too!
With only 49 grams Gelu Carbon K1 is the lightest MTB saddle in the world. It's handmade in Portugal and its special paint job is custom made for Dream Bikes.