I don't know about HDMI, but the included EOSUtility and it's Remote Capture function can display a live feed from the sensor, via a USB connection. And this is true of all of Canon's DSLR models with Live View... I speak at "career day" at a local school each year and the last two years I've had my DSLR and laptop pointed at the class, with a "live view" of the students for them to see. Gets their attention....
