I made this rig. It's basically 3/4 inch PVC tubing that I spray painted matte black. I used 10 speed bicycle foam grips for the side and top handles. The ball mounts at the top are Big Blue Light and Motion ball mounts. The Go Pros are mounted using their bicycle handle bar mounts.
I'm going to make rig 2.0 in a few weeks. The biggest upgrade will be adding about 2 pounds of lead to give it some stability. It's too light as it is and it takes a lot of effort to make a steady shot.
The lights that are shown in the picture are UK Aqualights. Do not waste your money on these. I repeat do not waste your money on these. I have literally sent them back to UK no less than 10 times because the housing keeps cracking on me. They sit on a shelf now and are basically unusable because they'll flood if I take them underwater. I repeat do not waste your money on these.
My other video rig is a Nauticam housing for the Blackmagic Pocket Cinema camera. I have my Go Pro mounted for B-roll footage. The lights are Light and Motion GoBe's. They're a decent light but not enough for this rig. In the future I will pick up a pair of Stella 2000 video lights for it.
The biggest issue with mask mounted cameras is that you get bubble interference when you exhale and every time you turn your head your camera is going to pan. It can be a real pain in the butt to watch. Wrist mounted is okay but you suffer from the same issues when it comes to panning. Every time you move your wrist it's going to pan that camera around.
Your best bet in my opinion for usable footage is to buy or build a tray. It should have some weight to it as this will help steady your shots. You'll want to invest in a decent light(s). Go Pros need a lot of light because of their small sensor and lens. In addition you'll also want to get the appropriate filters for the environment you'll be shooting in. Red for blue water, magenta for green water. Personally, I use Snake River Prototyping filters. If you do these things you can get some good footage out of your Go Pro.