I wanted a cheap and easy way to mount my iPad on the wall of my kitchen (which I've found to be the room in which I most use it). This is my fifteen minute solution.
Step 1: 1/2" Aluminum Trim Channel
I'd previously built an iPhone holder out of 1/2" aluminum trim channel and so decided it would be a fine material for this project (it's durable and easy to machine). The 1/2" channel is a bit larger than the depth of the iPad but it works well enough. You won't need very much as the iPad is only seven and a half inches wide.
Step 2: Tabs, Slots and Mounting Holes
You'll need to cut some slots and tabs for access to the "Home" button, the power cable and access to the mounting holes.
Cutting aluminum will probably throw a lot of aluminum dust into air. Probably you'll want to do this away from your electronics.
Also, you should wear eye protection. I didn't, because I like to live on the edge.
The aluminum might get hot while you're cutting it. Maybe you should use a vice or a pliers like I did. When it got too hot I ran it under cold water. No worries here, aluminum won't rust.
Step 3: Mounting the Rail
I used a couple of 1 1/2" pan head screws. Feel free to use whatever you have lying around. There's enough space between the iPad and the edges of the aluminum trim that most screw heads won't bind against the delicate chassis of the iPad causing unsightly scratches. If that sort of thing concerns you you might try covering the screw heads with a layer of epoxy or silicone caulk or some other sort of thing padding.
I was able to screw straight into a stud. If you're not so lucky you will probably want to consider using some anchors appropriate to the wall to which this is being attached.