We’ve been prototyping a new exchange architecture which combines the trustless, non-custodial features of DEXs with the regulatory, performance and privacy features of CEXs. You can read more about the motivating factors here.
Much of the information from the above post has been condensed into a short 3-minute video which describes the problem as it stands today, outlines a high-level description of a validium solution and lists some potential features of a validium solution as a layer 3 app-specific rollup.