Possible solution...very cheap!
Friction Tape.
http://t2.gstatic.com/images?q=tbn:ANd9GcQL9Z9NUyZQ2pvhUh_eVcf-SpJmylw4ThXhZuy9YRC-bjv8_O0y
It's the stuff that electricians used MANY years ago. In house wiring, they used to
solder the bared wires together, then wrap in rubber insulating tape, which would then be covered in friction tape. It's also an ideal thing to use to add grip to a stickball bat.
More recently, I was having trouble holding on to guitar plectrums; they'd always slip and slide around and I never felt I had a good grip on it. Friction tape totally fixed that.
Recently I got a Galaxy s3 which has tons of usefulness, but it begged to be protected by a sturdy case. My old LG Optimus felt way sturdier and had a subtle non-slip surface. I used it over two years without a problem. It survived many drops to unforgiving surfaces. No way would I expect that from the Galaxy.
Enter the Otterbox Commuter. Nice design, nice execution. Even nice price-point.
However, I believe they coated it in teflon. No need to say more about that.
Enter Friction tape. Two strips across the back, making sure to cut the ends just long enough to tuck all the way around the edge of the case, and end just at the edge of the screen.
View attachment 65567
View attachment 65568
It might take a couple of attempts. Helps, too to press the ends of the tape firmly in place.
I'll give this arrangement a few days of normal use and report back.