Steve Mann has been working on head mounted displays, true, but he's been focusing on local horsepower wearable computers.
Ultimately, I don't think google glass is anything more than a PR project to remove the stigma of google as ripoff artists and to make it look like they're innovative.
Given current technology, glass on wifi should have about 20 minutes of battery life, maybe an hour. Which makes them pretty useless.
There's really quite a difference between a wearable computer (what Mann works on) and a bluetooth headset with integrated display (what glass is.)