This goes through my mind every time I ride the NYC subway to work.
So I decided to make a strap, that would support the iPad, as well as prevent someone from pulling it from me on a train.
Step 1: Belkin Grip View Silicon Sleeve
because I knew I would be modifying it and didn't care until my ultimate case came along.
Here is the link for one:
Step 2: Building the mount
A flat head screw, and a grommet washer, a small washer and a flat locking nut.
(the flatter and the wider the better) a pliers, brad all and some HEAT
Step 3: Holy iPad Batman!
(I used a sharpie to mark direct center of the iPad, just the center of the apple)
Step 4: Preparing the Strap
Being extra geeky, I used double stick foam tape (1/4") and black tape as re-enforcement.