The stiffness of a tube is controlled by two factors: the metal stiffness, characterized by the Modulus of Elasticity or Young's Modulus, and a shape factor known as the Area Moment of Inertia.
Ti as a metal is not as stiff as steel (Young's modulus is lower), but stiffer than aluminum. As you know, most aluminum frames are bone rattling stiff. Why? because the shape factor, Moment of Inertia, is high (large diameter tubes and fairly thick)- Aluminum as a material is prone to cracking so the designers make the frame stiff so it doesn't flex which leads to aluminum frame failure.
So going back to your Ti frame, it's easy to build a stiff Ti frame by increasing the tubing diameters and tube thickness since this increases the shape factor. Look for a frame with a 1-1/2" diameter down tube and 1-3/8" seat tube, this frame will be nice and stiff. No need to monkey with triple triangle mumbo jumbo - just up the tube diameters. Very simple.