Windows Central has reported that it has some concrete information on the show.
Managing editor, Jez Corden, has reported that the showcase could be titled Xbox Developer_Direct, and will allegedly air on January 25 at 8PM GMT / 9PM CET / 12PM PT / 3PM ET.
Corden reports hearing about an Xbox Showcase back in December but has “since been able to lock the information down with a variety of sources familiar with Microsoft’s plans.”