Stew,
There is no BB30 adaptor that I know of as the shell is not only oversized, but wider as well.
The shell was originally designed for a few distinct reasons; to allow a larger surface area for welding when using oversized tubing (nice for Ti) or suspension components, larger diameter allows for a larger spindle of decreased wall thickness to result in lighter weight and increased rigidity, and to provide a product that had universally available bearing parts.
Will this make every other bb in the world obselete...nope, there will always be the solid square taper, but it is an improvement in design for modern componentry's design and performance.
cheers,
rody
Ps... If I was to buy any Ti builders frame myself, it would be a Potts. Steve has mentored many of those listed, fwiw.