This follows theof a recently registered xboxevent.com domain name by NeoGAF. The domain was registered by Eventcore, which was formerly called US Techs.
Back when Eventcore was US Techs, it also did Microsoft's E3 keynote last year.
Major Nelson tweeted during the "See the Future" event, "Announce a console without actually showing a console? That's one approach." This would indicate that Microsoft could be showing actual hardware at their own event.