http://www.amazon.com/Looxcie-Wearable-Bluetooth-Camcorder-C...
Of course, there are cheaper and more discrete solutions, like this one [1], the one you linked is probably even more conspicuous than Glass, and half-VGA resolution is pretty bad. I use the linked one as cheap motocycle cam, and it is hard to aim properly with no viewfinder, but what you can expect for about $ 10.
[1]: https://www.youtube.com/watch?v=uj26JjSiazQ (I hope it's the right video. Corporate firewall won't let me go on youtube)
There's lots of devices like this - I also remember some systems that cops wear that just clips onto the front of your shirt and looks kind of like a pager. Glass isn't particularly novel in this regard (except for maybe its connectivity via wifi).